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<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="アニメーション図解ワンクリック実行データ構造とアルゴリズムチュートリアル">
<meta name="description" content="アニメーション図解ワンクリック実行コードで学べるデータ構造とアルゴリズムの入門書">
<meta name="author" content="krahets">
@@ -117,7 +117,7 @@
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</svg>
<span>日本語版審閱者を募集しています!詳細<a href="https://github.com/krahets/hello-algo/blob/main/ja/CONTRIBUTING.md">CONTRIBUTING.md</a>参照してください。</span>
<span>日本語版のレビュアーを募集しています。詳しく<a href="/ja/chapter_appendix/contribution/">こちら</a>ご覧ください。</span>
</div>
</div>
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<span class="md-ellipsis">
はじめに
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<span class="md-nav__icon md-icon"></span>
はじめに
</label>
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<span class="md-ellipsis">
1.1 &nbsp; アルゴリズムはどこにでもある
1.1 &nbsp; アルゴリズムは至るところにある
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<span class="md-ellipsis">
1.2 &nbsp; アルゴリズムとは何か
1.2 &nbsp; アルゴリズムとは
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<span class="md-ellipsis">
2.1 &nbsp; アルゴリズム効率評価
2.1 &nbsp; アルゴリズム効率評価
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<span class="md-ellipsis">
3.3 &nbsp; 数値の符号化 *
3.3 &nbsp; 数値エンコーディング *
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<span class="md-ellipsis">
3.4 &nbsp; 文字の符号化 *
3.4 &nbsp; 文字エンコーディング *
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<span class="md-ellipsis">
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
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<span class="md-nav__icon md-icon"></span>
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
</label>
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<span class="md-ellipsis">
6.1 &nbsp; ハッシュ
6.1 &nbsp; ハッシュテーブル
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<span class="md-ellipsis">
7.5 &nbsp; AVL木 *
7.5 &nbsp; AVL 木 *
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<span class="md-ellipsis">
8.2 &nbsp; ヒープ構築操作
8.2 &nbsp; ヒープ構築
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<span class="md-ellipsis">
10.2 &nbsp; 二分探索の挿入
10.2 &nbsp; 二分探索の挿入位置
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<span class="md-ellipsis">
10.4 &nbsp; ハッシュ最適化戦略
10.4 &nbsp; ハッシュによる最適化戦略
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<span class="md-ellipsis">
10.5 &nbsp; 探索アルゴリズムの再認識
10.5 &nbsp; 探索アルゴリズム再考
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<span class="md-ellipsis">
12.1 &nbsp; 分割統治アルゴリズム
12.1 &nbsp; 分割統治
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<span class="md-ellipsis">
12.3 &nbsp; 木の構築問題
12.3 &nbsp; 二分木の構築問題
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<span class="md-ellipsis">
12.4 &nbsp; ハノイの塔問題
12.4 &nbsp; ハノイの塔問題
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<span class="md-ellipsis">
13.3 &nbsp; 部分集合和問題
13.3 &nbsp; 部分和問題
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<span class="md-ellipsis">
13.4 &nbsp; Nクイーン問題
13.4 &nbsp; n クイーン問題
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<span class="md-ellipsis">
14.1 &nbsp; 動的計画法の初歩
14.1 &nbsp; 動的計画法入門
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<span class="md-ellipsis">
14.2 &nbsp; DP 問題特性
14.2 &nbsp; 動的計画法の問題特性
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<span class="md-ellipsis">
14.3 &nbsp; DP の解法の考え方
14.3 &nbsp; 動的計画法の問題解決の考え方
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<span class="md-ellipsis">
14.4 &nbsp; 0-1ナップサック問題
14.4 &nbsp; 0-1 ナップサック問題
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<span class="md-ellipsis">
15.1 &nbsp; 貪欲アルゴリズム
15.1 &nbsp; 貪欲
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<span class="md-ellipsis">
16.2 &nbsp; 一緒に作に参加する
16.2 &nbsp; 一緒に作に参加しましょう
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<p><img alt="ヒープ" class="cover-image" src="../assets/covers/chapter_heap.jpg" /></p>
<div class="admonition abstract">
<p class="admonition-title">Abstract</p>
<p>ヒープは山とその険しい峰のように、層をなして起伏し、それぞれが独特の形を持っています</p>
<p>各山の頂は散らばった高さで上下しますが、最も高いものが常に最初に注目を集めます</p>
<p>ヒープは連なる山々の峰のように、幾重にも重なり、さまざまな形をしている</p>
<p>いくつもの山の高さはまちまちだが、最も高い峰がいつも最初に目に入る</p>
</div>
<h2 id="_1">章の内容<a class="headerlink" href="#_1" title="Permanent link">&para;</a></h2>
<ul>
<li><a href="heap/">8.1 &nbsp; ヒープ</a></li>
<li><a href="build_heap/">8.2 &nbsp; ヒープ構築操作</a></li>
<li><a href="build_heap/">8.2 &nbsp; ヒープ構築</a></li>
<li><a href="top_k/">8.3 &nbsp; Top-k 問題</a></li>
<li><a href="summary/">8.4 &nbsp; まとめ</a></li>
</ul>
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<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="アニメーション図解ワンクリック実行データ構造とアルゴリズムチュートリアル">
<meta name="description" content="アニメーション図解ワンクリック実行コードで学べるデータ構造とアルゴリズムの入門書">
<meta name="author" content="krahets">
@@ -117,7 +117,7 @@
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</svg>
<span>日本語版審閱者を募集しています!詳細<a href="https://github.com/krahets/hello-algo/blob/main/ja/CONTRIBUTING.md">CONTRIBUTING.md</a>参照してください。</span>
<span>日本語版のレビュアーを募集しています。詳しく<a href="/ja/chapter_appendix/contribution/">こちら</a>ご覧ください。</span>
</div>
</div>
@@ -341,7 +341,7 @@
<span class="md-ellipsis">
はじめに
@@ -358,7 +358,7 @@
<span class="md-nav__icon md-icon"></span>
はじめに
</label>
@@ -618,7 +618,7 @@
<span class="md-ellipsis">
1.1 &nbsp; アルゴリズムはどこにでもある
1.1 &nbsp; アルゴリズムは至るところにある
@@ -646,7 +646,7 @@
<span class="md-ellipsis">
1.2 &nbsp; アルゴリズムとは何か
1.2 &nbsp; アルゴリズムとは
@@ -783,7 +783,7 @@
<span class="md-ellipsis">
2.1 &nbsp; アルゴリズム効率評価
2.1 &nbsp; アルゴリズム効率評価
@@ -1060,7 +1060,7 @@
<span class="md-ellipsis">
3.3 &nbsp; 数値の符号化 *
3.3 &nbsp; 数値エンコーディング *
@@ -1088,7 +1088,7 @@
<span class="md-ellipsis">
3.4 &nbsp; 文字の符号化 *
3.4 &nbsp; 文字エンコーディング *
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<span class="md-ellipsis">
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
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<span class="md-nav__icon md-icon"></span>
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
</label>
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<span class="md-ellipsis">
6.1 &nbsp; ハッシュ
6.1 &nbsp; ハッシュテーブル
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<span class="md-ellipsis">
7.5 &nbsp; AVL木 *
7.5 &nbsp; AVL 木 *
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<span class="md-ellipsis">
8.2 &nbsp; ヒープ構築操作
8.2 &nbsp; ヒープ構築
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<a href="#1" class="md-nav__link">
<span class="md-ellipsis">
1. &nbsp; 重要な復習
1. &nbsp; 重要なポイントの振り返り
</span>
</a>
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<span class="md-ellipsis">
10.2 &nbsp; 二分探索の挿入
10.2 &nbsp; 二分探索の挿入位置
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<span class="md-ellipsis">
10.4 &nbsp; ハッシュ最適化戦略
10.4 &nbsp; ハッシュによる最適化戦略
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<span class="md-ellipsis">
10.5 &nbsp; 探索アルゴリズムの再認識
10.5 &nbsp; 探索アルゴリズム再考
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<span class="md-ellipsis">
12.1 &nbsp; 分割統治アルゴリズム
12.1 &nbsp; 分割統治
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<span class="md-ellipsis">
12.3 &nbsp; 木の構築問題
12.3 &nbsp; 二分木の構築問題
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<span class="md-ellipsis">
12.4 &nbsp; ハノイの塔問題
12.4 &nbsp; ハノイの塔問題
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<span class="md-ellipsis">
13.3 &nbsp; 部分集合和問題
13.3 &nbsp; 部分和問題
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<span class="md-ellipsis">
13.4 &nbsp; Nクイーン問題
13.4 &nbsp; n クイーン問題
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<span class="md-ellipsis">
14.1 &nbsp; 動的計画法の初歩
14.1 &nbsp; 動的計画法入門
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<span class="md-ellipsis">
14.2 &nbsp; DP 問題特性
14.2 &nbsp; 動的計画法の問題特性
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<span class="md-ellipsis">
14.3 &nbsp; DP の解法の考え方
14.3 &nbsp; 動的計画法の問題解決の考え方
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<span class="md-ellipsis">
14.4 &nbsp; 0-1ナップサック問題
14.4 &nbsp; 0-1 ナップサック問題
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<span class="md-ellipsis">
15.1 &nbsp; 貪欲アルゴリズム
15.1 &nbsp; 貪欲
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<span class="md-ellipsis">
16.2 &nbsp; 一緒に作に参加する
16.2 &nbsp; 一緒に作に参加しましょう
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<a href="#1" class="md-nav__link">
<span class="md-ellipsis">
1. &nbsp; 重要な復習
1. &nbsp; 重要なポイントの振り返り
</span>
</a>
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<!-- Page content -->
<h1 id="84">8.4 &nbsp; まとめ<a class="headerlink" href="#84" title="Permanent link">&para;</a></h1>
<h3 id="1">1. &nbsp; 重要な復習<a class="headerlink" href="#1" title="Permanent link">&para;</a></h3>
<h3 id="1">1. &nbsp; 重要なポイントの振り返り<a class="headerlink" href="#1" title="Permanent link">&para;</a></h3>
<ul>
<li>ヒープは完二分木で、その構築性質に基づいて最大ヒープまたは最小ヒープに分類できます。最大ヒープの先頭要素は最大で、最小ヒープの先頭要素は最小です</li>
<li>優先度キューは、デキューの優先度を持つキューとして定義され、通常ヒープを使用して実装されます</li>
<li>ヒープの一般的な操作とそれに対応する時間計算量には以下があります:ヒープへの要素挿入<span class="arithmatex">\(O(\log n)\)</span>ヒープからの先頭要素削除<span class="arithmatex">\(O(\log n)\)</span>ヒープの先頭要素へのアクセス<span class="arithmatex">\(O(1)\)</span></li>
<li>二分木は配列で表現するのに適しているため、ヒープは一般的に配列を使用して格納されます</li>
<li>ヒープ化操作はヒープの性質を維持するために使用され、ヒープの挿入操作と削除操作の両方で使用されます</li>
<li><span class="arithmatex">\(n\)</span>個の要素入力して与えられた場合のヒープ構築時間計算量は<span class="arithmatex">\(O(n)\)</span>最適化でき、これは非常に効率的で</li>
<li>Top-kは古典的なアルゴリズム問題で、ヒープデータ構造を使用して効率的に解でき、時間計算量は<span class="arithmatex">\(O(n \log k)\)</span>です</li>
<li>ヒープは完二分木であり、条件の違いによって最大ヒープ最小ヒープに分けられる。最大(最小)ヒープの根の要素は最大値(最小値)である</li>
<li>優先度付きキューは、取り出し時に優先度が考慮されるキューであり、通常ヒープを用いて実装され</li>
<li>ヒープの代表的な操作とそれに対応する時間計算量には要素挿入 <span class="arithmatex">\(O(\log n)\)</span>根の要素削除 <span class="arithmatex">\(O(\log n)\)</span>根の要素へのアクセス <span class="arithmatex">\(O(1)\)</span> などがある</li>
<li>二分木は配列で表現するのに非常に適しているため、通常は配列を使ってヒープを格納する</li>
<li>ヒープ化操作はヒープの性質を保つために用いられ、挿入操作と削除操作の両方で使用され</li>
<li><span class="arithmatex">\(n\)</span> 個の要素入力してヒープ構築する時間計算量は <span class="arithmatex">\(O(n)\)</span> まで最適化でき、非常に効率的である</li>
<li>Top-k は古典的なアルゴリズム問題であり、ヒープ構造を用いることで効率的に解くことができ、時間計算量は <span class="arithmatex">\(O(n \log k)\)</span> である</li>
</ul>
<h3 id="2-q-a">2. &nbsp; Q &amp; A<a class="headerlink" href="#2-q-a" title="Permanent link">&para;</a></h3>
<p><strong>Q</strong>: データ構造の「ヒープ」とメモリ管理の「ヒープ」は同じ概念ですか?</p>
<p>この2つは、どちらも「ヒープ」と呼ばれますが、同じ概念ではありません。コンピュータシステムメモリヒープは動的メモリ割り当ての一部で、プログラム実行中にデータを格納するために使用できます。プログラムは、オブジェクトや配列などの複雑な構造を格納するために、一定量のヒープメモリを要求できます。割り当てられたデータが不要になったときは、メモリリークを防ぐためにプログラムがこのメモリを解放する必要があります。スタックメモリと比較して、ヒープメモリの管理と使用にはより多くの注意が必要で、不適切な使用はメモリリークやダングリングポインタにつながる可能性があります</p>
<p><strong>Q</strong>データ構造の「ヒープ」とメモリ管理の「ヒープ」は同じ概念ですか?</p>
<p>両者は同じ概念ではなく、たまたまどちらも「ヒープ」と呼ばれているだけである。コンピュータシステムメモリにおけるヒープは動的メモリ割り当ての一部であり、プログラム実行時にこれを使ってデータを格納できる。プログラムは一定量のヒープメモリを要求し、オブジェクトや配列などの複雑な構造を保存できる。これらのデータが不要になったときは、メモリリークを防ぐためにのメモリを解放する必要があ。スタックメモリと比べると、ヒープメモリの管理と使用にはより慎重さが求められ、不適切に扱うとメモリリークやダングリングポインタなどの問題を引き起こす可能性があ</p>
<!-- Source file information -->
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<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="アニメーション図解ワンクリック実行データ構造とアルゴリズムチュートリアル">
<meta name="description" content="アニメーション図解ワンクリック実行コードで学べるデータ構造とアルゴリズムの入門書">
<meta name="author" content="krahets">
@@ -39,7 +39,7 @@
<title>8.3 Top-k問題 - Hello アルゴリズム</title>
<title>8.3 Top-k 問題 - Hello アルゴリズム</title>
@@ -117,7 +117,7 @@
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</svg>
<span>日本語版審閱者を募集しています!詳細<a href="https://github.com/krahets/hello-algo/blob/main/ja/CONTRIBUTING.md">CONTRIBUTING.md</a>参照してください。</span>
<span>日本語版のレビュアーを募集しています。詳しく<a href="/ja/chapter_appendix/contribution/">こちら</a>ご覧ください。</span>
</div>
</div>
@@ -152,7 +152,7 @@
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
8.3 &nbsp; Top-k問題
8.3 &nbsp; Top-k 問題
</span>
</div>
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<span class="md-ellipsis">
はじめに
@@ -358,7 +358,7 @@
<span class="md-nav__icon md-icon"></span>
はじめに
</label>
@@ -618,7 +618,7 @@
<span class="md-ellipsis">
1.1 &nbsp; アルゴリズムはどこにでもある
1.1 &nbsp; アルゴリズムは至るところにある
@@ -646,7 +646,7 @@
<span class="md-ellipsis">
1.2 &nbsp; アルゴリズムとは何か
1.2 &nbsp; アルゴリズムとは
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<span class="md-ellipsis">
2.1 &nbsp; アルゴリズム効率評価
2.1 &nbsp; アルゴリズム効率評価
@@ -1060,7 +1060,7 @@
<span class="md-ellipsis">
3.3 &nbsp; 数値の符号化 *
3.3 &nbsp; 数値エンコーディング *
@@ -1088,7 +1088,7 @@
<span class="md-ellipsis">
3.4 &nbsp; 文字の符号化 *
3.4 &nbsp; 文字エンコーディング *
@@ -1591,7 +1591,7 @@
<span class="md-ellipsis">
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
@@ -1613,7 +1613,7 @@
<span class="md-nav__icon md-icon"></span>
第 6 章 &nbsp; ハッシュ
第 6 章 &nbsp; ハッシュテーブル
</label>
@@ -1635,7 +1635,7 @@
<span class="md-ellipsis">
6.1 &nbsp; ハッシュ
6.1 &nbsp; ハッシュテーブル
@@ -1942,7 +1942,7 @@
<span class="md-ellipsis">
7.5 &nbsp; AVL木 *
7.5 &nbsp; AVL 木 *
@@ -2107,7 +2107,7 @@
<span class="md-ellipsis">
8.2 &nbsp; ヒープ構築操作
8.2 &nbsp; ヒープ構築
@@ -2189,10 +2189,10 @@
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#831-1" class="md-nav__link">
<a href="#831" class="md-nav__link">
<span class="md-ellipsis">
8.3.1 &nbsp; 方法1:反復選択
8.3.1 &nbsp; 方法一:走査による選択
</span>
</a>
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</li>
<li class="md-nav__item">
<a href="#832-2" class="md-nav__link">
<a href="#832" class="md-nav__link">
<span class="md-ellipsis">
8.3.2 &nbsp; 方法2:ソート
8.3.2 &nbsp; 方法:ソート
</span>
</a>
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</li>
<li class="md-nav__item">
<a href="#833-3" class="md-nav__link">
<a href="#833" class="md-nav__link">
<span class="md-ellipsis">
8.3.3 &nbsp; 方法3:ヒープ
8.3.3 &nbsp; 方法:ヒープ
</span>
</a>
@@ -2574,7 +2574,7 @@
<span class="md-ellipsis">
10.2 &nbsp; 二分探索の挿入
10.2 &nbsp; 二分探索の挿入位置
@@ -2630,7 +2630,7 @@
<span class="md-ellipsis">
10.4 &nbsp; ハッシュ最適化戦略
10.4 &nbsp; ハッシュによる最適化戦略
@@ -2658,7 +2658,7 @@
<span class="md-ellipsis">
10.5 &nbsp; 探索アルゴリズムの再認識
10.5 &nbsp; 探索アルゴリズム再考
@@ -3196,7 +3196,7 @@
<span class="md-ellipsis">
12.1 &nbsp; 分割統治アルゴリズム
12.1 &nbsp; 分割統治
@@ -3252,7 +3252,7 @@
<span class="md-ellipsis">
12.3 &nbsp; 木の構築問題
12.3 &nbsp; 二分木の構築問題
@@ -3280,7 +3280,7 @@
<span class="md-ellipsis">
12.4 &nbsp; ハノイの塔問題
12.4 &nbsp; ハノイの塔問題
@@ -3473,7 +3473,7 @@
<span class="md-ellipsis">
13.3 &nbsp; 部分集合和問題
13.3 &nbsp; 部分和問題
@@ -3501,7 +3501,7 @@
<span class="md-ellipsis">
13.4 &nbsp; Nクイーン問題
13.4 &nbsp; n クイーン問題
@@ -3642,7 +3642,7 @@
<span class="md-ellipsis">
14.1 &nbsp; 動的計画法の初歩
14.1 &nbsp; 動的計画法入門
@@ -3670,7 +3670,7 @@
<span class="md-ellipsis">
14.2 &nbsp; DP 問題特性
14.2 &nbsp; 動的計画法の問題特性
@@ -3698,7 +3698,7 @@
<span class="md-ellipsis">
14.3 &nbsp; DP の解法の考え方
14.3 &nbsp; 動的計画法の問題解決の考え方
@@ -3726,7 +3726,7 @@
<span class="md-ellipsis">
14.4 &nbsp; 0-1ナップサック問題
14.4 &nbsp; 0-1 ナップサック問題
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<span class="md-ellipsis">
15.1 &nbsp; 貪欲アルゴリズム
15.1 &nbsp; 貪欲
@@ -4164,7 +4164,7 @@
<span class="md-ellipsis">
16.2 &nbsp; 一緒に作に参加する
16.2 &nbsp; 一緒に作に参加しましょう
@@ -4307,10 +4307,10 @@
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#831-1" class="md-nav__link">
<a href="#831" class="md-nav__link">
<span class="md-ellipsis">
8.3.1 &nbsp; 方法1:反復選択
8.3.1 &nbsp; 方法一:走査による選択
</span>
</a>
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</li>
<li class="md-nav__item">
<a href="#832-2" class="md-nav__link">
<a href="#832" class="md-nav__link">
<span class="md-ellipsis">
8.3.2 &nbsp; 方法2:ソート
8.3.2 &nbsp; 方法:ソート
</span>
</a>
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</li>
<li class="md-nav__item">
<a href="#833-3" class="md-nav__link">
<a href="#833" class="md-nav__link">
<span class="md-ellipsis">
8.3.3 &nbsp; 方法3:ヒープ
8.3.3 &nbsp; 方法:ヒープ
</span>
</a>
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<!-- Page content -->
<h1 id="83-top-k">8.3 &nbsp; Top-k問題<a class="headerlink" href="#83-top-k" title="Permanent link">&para;</a></h1>
<h1 id="83-top-k">8.3 &nbsp; Top-k 問題<a class="headerlink" href="#83-top-k" title="Permanent link">&para;</a></h1>
<div class="admonition question">
<p class="admonition-title">Question</p>
<p>長さ<span class="arithmatex">\(n\)</span>の順序付けられていない配列<code>nums</code>が与えられたとき、配列内最大<span class="arithmatex">\(k\)</span>個の要素を返してください。</p>
<p>長さ <span class="arithmatex">\(n\)</span> の未整列配列 <code>nums</code> が与えられたとき、配列内最大<span class="arithmatex">\(k\)</span> 個の要素を返してください。</p>
</div>
<p>この問題について、まず2つの直接的な解法を紹介し、次により効率的なヒープベースの方法を説明します。</p>
<h2 id="831-1">8.3.1 &nbsp; 方法1:反復選択<a class="headerlink" href="#831-1" title="Permanent link">&para;</a></h2>
<p>図に示すように<span class="arithmatex">\(k\)</span>回の反復を実行し、各回で<span class="arithmatex">\(1\)</span>番目<span class="arithmatex">\(2\)</span>番目<span class="arithmatex">\(\dots\)</span><span class="arithmatex">\(k\)</span>番目に大きい要素を抽出できます。時間計算量は<span class="arithmatex">\(O(nk)\)</span>です。</p>
<p>この方法は<span class="arithmatex">\(k \ll n\)</span>の場合にのみ適していま<span class="arithmatex">\(k\)</span><span class="arithmatex">\(n\)</span>に近い場合、時間計算量は<span class="arithmatex">\(O(n^2)\)</span>に近づき、非常に時間がかかります。</p>
<p><img alt="最大k個の要素を反復的に見つける" class="animation-figure" src="../top_k.assets/top_k_traversal.png" /></p>
<p align="center"> 図 8-6 &nbsp; 最大k個の要素を反復的に見つける </p>
<p>この問題について、まずは発想が比較的直接的な 2 つの解法を紹介し、その後でより効率の高いヒープ解法を紹介します。</p>
<h2 id="831">8.3.1 &nbsp; 方法一:走査による選択<a class="headerlink" href="#831" title="Permanent link">&para;</a></h2>
<p>以下の図に示すように <span class="arithmatex">\(k\)</span> 回の走査を行い、各ラウンドでそれぞれ第 <span class="arithmatex">\(1\)</span><span class="arithmatex">\(2\)</span><span class="arithmatex">\(\dots\)</span><span class="arithmatex">\(k\)</span> 位の要素を取り出すことができます。時間計算量は <span class="arithmatex">\(O(nk)\)</span> です。</p>
<p>この方法は <span class="arithmatex">\(k \ll n\)</span> の場合にしか適していません<span class="arithmatex">\(k\)</span><span class="arithmatex">\(n\)</span> にかなり近いと、時間計算量は <span class="arithmatex">\(O(n^2)\)</span> に近づき、非常に時間がかかるためです。</p>
<p><img alt="走査によって最大の k 個の要素を探す" class="animation-figure" src="../top_k.assets/top_k_traversal.png" /></p>
<p align="center"> 図 8-6 &nbsp; 走査によって最大の k 個の要素を探す </p>
<div class="admonition tip">
<p class="admonition-title">Tip</p>
<p><span class="arithmatex">\(k = n\)</span>の場合、完全に順序付けられたシーケンスを得ることができ、こは「選択ソート」アルゴリズムと同等です。</p>
<p><span class="arithmatex">\(k = n\)</span> のとき、完全な昇順列を得ることができ、この場合は「選択ソート」アルゴリズムと等価になります。</p>
</div>
<h2 id="832-2">8.3.2 &nbsp; 方法2:ソート<a class="headerlink" href="#832-2" title="Permanent link">&para;</a></h2>
<p>図に示すように、まず配列<code>nums</code>をソートし、次に最後の<span class="arithmatex">\(k\)</span>個の要素を返すことができます。時間計算量は<span class="arithmatex">\(O(n \log n)\)</span>です。</p>
<p>明らかに、この方法はタスクを「やりすぎ」ています。最大<span class="arithmatex">\(k\)</span>個の要素を見つけるだけでよく、他の要素をソートする必要はありません</p>
<p><img alt="ソートによる最大k個の要素の発見" class="animation-figure" src="../top_k.assets/top_k_sorting.png" /></p>
<p align="center"> 図 8-7 &nbsp; ソートによる最大k個の要素の発見 </p>
<h2 id="832">8.3.2 &nbsp; 方法:ソート<a class="headerlink" href="#832" title="Permanent link">&para;</a></h2>
<p>以下の図に示すように、まず配列 <code>nums</code> をソートし、その後で右端の <span class="arithmatex">\(k\)</span> 個の要素を返すことができます。時間計算量は <span class="arithmatex">\(O(n \log n)\)</span> です。</p>
<p>明らかに、この方法は必要以上の処理を行っています。なぜなら、必要なのは最大の <span class="arithmatex">\(k\)</span> 個の要素を見つけることだけであり、他の要素をソートする必要はないからです</p>
<p><img alt="ソートによって最大の k 個の要素を探す" class="animation-figure" src="../top_k.assets/top_k_sorting.png" /></p>
<p align="center"> 図 8-7 &nbsp; ソートによって最大の k 個の要素を探す </p>
<h2 id="833-3">8.3.3 &nbsp; 方法3:ヒープ<a class="headerlink" href="#833-3" title="Permanent link">&para;</a></h2>
<p>以下のプロセスに示すように、ヒープに基づいてTop-k問題をより効率的に解決できます。</p>
<h2 id="833">8.3.3 &nbsp; 方法:ヒープ<a class="headerlink" href="#833" title="Permanent link">&para;</a></h2>
<p>ヒープを用いることで、Top-k 問題をより効率的に解くことができます。手順は以下の図のとおりです。</p>
<ol>
<li>最小ヒープを初期化します。先頭要素が最小になります。</li>
<li>まず配列の最初の<span class="arithmatex">\(k\)</span>個の要素をヒープ挿入します。</li>
<li><span class="arithmatex">\(k + 1\)</span>番目の要素から開始し、現在の要素がヒープの先頭要素より大きい場合、ヒープの先頭要素を削除し、現在の要素をヒープ挿入します。</li>
<li>走査完了した後、ヒープには最大<span class="arithmatex">\(k\)</span>個の要素が含まれています。</li>
<li>最小ヒープを初期化し、そのヒープ頂点の要素が最小となるようにします。</li>
<li>まず配列の先頭 <span class="arithmatex">\(k\)</span> 個の要素を順にヒープ挿入します。</li>
<li><span class="arithmatex">\(k + 1\)</span> 番目の要素から開始し、現在の要素がヒープ頂点の要素より大きければ、ヒープ頂点の要素を取り出し、現在の要素をヒープ挿入します。</li>
<li>走査完了した後、ヒープに保持されているのが最大の <span class="arithmatex">\(k\)</span> 個の要素す。</li>
</ol>
<div class="tabbed-set tabbed-alternate" data-tabs="1:9"><input checked="checked" id="__tabbed_1_1" name="__tabbed_1" type="radio" /><input id="__tabbed_1_2" name="__tabbed_1" type="radio" /><input id="__tabbed_1_3" name="__tabbed_1" type="radio" /><input id="__tabbed_1_4" name="__tabbed_1" type="radio" /><input id="__tabbed_1_5" name="__tabbed_1" type="radio" /><input id="__tabbed_1_6" name="__tabbed_1" type="radio" /><input id="__tabbed_1_7" name="__tabbed_1" type="radio" /><input id="__tabbed_1_8" name="__tabbed_1" type="radio" /><input id="__tabbed_1_9" name="__tabbed_1" type="radio" /><div class="tabbed-labels"><label for="__tabbed_1_1">&lt;1&gt;</label><label for="__tabbed_1_2">&lt;2&gt;</label><label for="__tabbed_1_3">&lt;3&gt;</label><label for="__tabbed_1_4">&lt;4&gt;</label><label for="__tabbed_1_5">&lt;5&gt;</label><label for="__tabbed_1_6">&lt;6&gt;</label><label for="__tabbed_1_7">&lt;7&gt;</label><label for="__tabbed_1_8">&lt;8&gt;</label><label for="__tabbed_1_9">&lt;9&gt;</label></div>
<div class="tabbed-content">
<div class="tabbed-block">
<p><img alt="ヒープに基づく最大k個の要素の発見" class="animation-figure" src="../top_k.assets/top_k_heap_step1.png" /></p>
<p><img alt="ヒープに基づいて最大の k 個の要素を探す" class="animation-figure" src="../top_k.assets/top_k_heap_step1.png" /></p>
</div>
<div class="tabbed-block">
<p><img alt="top_k_heap_step2" class="animation-figure" src="../top_k.assets/top_k_heap_step2.png" /></p>
@@ -4437,22 +4437,22 @@
</div>
</div>
</div>
<p align="center"> 図 8-8 &nbsp; ヒープに基づく最大k個の要素の発見 </p>
<p align="center"> 図 8-8 &nbsp; ヒープに基づいて最大の k 個の要素を探す </p>
<p>サンプルコードは以下のりです</p>
<p>サンプルコードは以下のとおりです</p>
<div class="tabbed-set tabbed-alternate" data-tabs="2:13"><input checked="checked" id="__tabbed_2_1" name="__tabbed_2" type="radio" /><input id="__tabbed_2_2" name="__tabbed_2" type="radio" /><input id="__tabbed_2_3" name="__tabbed_2" type="radio" /><input id="__tabbed_2_4" name="__tabbed_2" type="radio" /><input id="__tabbed_2_5" name="__tabbed_2" type="radio" /><input id="__tabbed_2_6" name="__tabbed_2" type="radio" /><input id="__tabbed_2_7" name="__tabbed_2" type="radio" /><input id="__tabbed_2_8" name="__tabbed_2" type="radio" /><input id="__tabbed_2_9" name="__tabbed_2" type="radio" /><input id="__tabbed_2_10" name="__tabbed_2" type="radio" /><input id="__tabbed_2_11" name="__tabbed_2" type="radio" /><input id="__tabbed_2_12" name="__tabbed_2" type="radio" /><input id="__tabbed_2_13" name="__tabbed_2" type="radio" /><div class="tabbed-labels"><label for="__tabbed_2_1">Python</label><label for="__tabbed_2_2">C++</label><label for="__tabbed_2_3">Java</label><label for="__tabbed_2_4">C#</label><label for="__tabbed_2_5">Go</label><label for="__tabbed_2_6">Swift</label><label for="__tabbed_2_7">JS</label><label for="__tabbed_2_8">TS</label><label for="__tabbed_2_9">Dart</label><label for="__tabbed_2_10">Rust</label><label for="__tabbed_2_11">C</label><label for="__tabbed_2_12">Kotlin</label><label for="__tabbed_2_13">Ruby</label></div>
<div class="tabbed-content">
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.py</span><pre><span></span><code><a id="__codelineno-0-1" name="__codelineno-0-1" href="#__codelineno-0-1"></a><span class="k">def</span><span class="w"> </span><span class="nf">top_k_heap</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span> <span class="nb">list</span><span class="p">[</span><span class="nb">int</span><span class="p">],</span> <span class="n">k</span><span class="p">:</span> <span class="nb">int</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">list</span><span class="p">[</span><span class="nb">int</span><span class="p">]:</span>
<a id="__codelineno-0-2" name="__codelineno-0-2" href="#__codelineno-0-2"></a><span class="w"> </span><span class="sd">&quot;&quot;&quot;ヒープを使用して配列の最大k個の要素を見つける&quot;&quot;&quot;</span>
<a id="__codelineno-0-2" name="__codelineno-0-2" href="#__codelineno-0-2"></a><span class="w"> </span><span class="sd">&quot;&quot;&quot;ヒープに基づいて配列の最大の k 個の要素を探す&quot;&quot;&quot;</span>
<a id="__codelineno-0-3" name="__codelineno-0-3" href="#__codelineno-0-3"></a> <span class="c1"># 最小ヒープを初期化</span>
<a id="__codelineno-0-4" name="__codelineno-0-4" href="#__codelineno-0-4"></a> <span class="n">heap</span> <span class="o">=</span> <span class="p">[]</span>
<a id="__codelineno-0-5" name="__codelineno-0-5" href="#__codelineno-0-5"></a> <span class="c1"># 配列の最初のk個の要素をヒープに入力</span>
<a id="__codelineno-0-5" name="__codelineno-0-5" href="#__codelineno-0-5"></a> <span class="c1"># 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-0-6" name="__codelineno-0-6" href="#__codelineno-0-6"></a> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">k</span><span class="p">):</span>
<a id="__codelineno-0-7" name="__codelineno-0-7" href="#__codelineno-0-7"></a> <span class="n">heapq</span><span class="o">.</span><span class="n">heappush</span><span class="p">(</span><span class="n">heap</span><span class="p">,</span> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
<a id="__codelineno-0-8" name="__codelineno-0-8" href="#__codelineno-0-8"></a> <span class="c1"># k+1番目の要素から、ヒープの長さをkに保つ</span>
<a id="__codelineno-0-8" name="__codelineno-0-8" href="#__codelineno-0-8"></a> <span class="c1"># k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-0-9" name="__codelineno-0-9" href="#__codelineno-0-9"></a> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="n">nums</span><span class="p">)):</span>
<a id="__codelineno-0-10" name="__codelineno-0-10" href="#__codelineno-0-10"></a> <span class="c1"># 現在の要素がヒープ先頭要素より大きい場合、ヒープ先頭要素を削除し、現在の要素をヒープに入力</span>
<a id="__codelineno-0-10" name="__codelineno-0-10" href="#__codelineno-0-10"></a> <span class="c1"># 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-0-11" name="__codelineno-0-11" href="#__codelineno-0-11"></a> <span class="k">if</span> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">&gt;</span> <span class="n">heap</span><span class="p">[</span><span class="mi">0</span><span class="p">]:</span>
<a id="__codelineno-0-12" name="__codelineno-0-12" href="#__codelineno-0-12"></a> <span class="n">heapq</span><span class="o">.</span><span class="n">heappop</span><span class="p">(</span><span class="n">heap</span><span class="p">)</span>
<a id="__codelineno-0-13" name="__codelineno-0-13" href="#__codelineno-0-13"></a> <span class="n">heapq</span><span class="o">.</span><span class="n">heappush</span><span class="p">(</span><span class="n">heap</span><span class="p">,</span> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
@@ -4460,17 +4460,17 @@
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.cpp</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="cm">/* ヒープを使用して配列の最大k個の要素を見つける */</span>
<div class="highlight"><span class="filename">top_k.cpp</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="cm">/* ヒープに基づいて配列の最大の k 個の要素を探す */</span>
<a id="__codelineno-1-2" name="__codelineno-1-2" href="#__codelineno-1-2"></a><span class="n">priority_queue</span><span class="o">&lt;</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">greater</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;&gt;</span><span class="w"> </span><span class="n">topKHeap</span><span class="p">(</span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="o">&amp;</span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-3" name="__codelineno-1-3" href="#__codelineno-1-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化</span>
<a id="__codelineno-1-4" name="__codelineno-1-4" href="#__codelineno-1-4"></a><span class="w"> </span><span class="n">priority_queue</span><span class="o">&lt;</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">greater</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">;</span>
<a id="__codelineno-1-5" name="__codelineno-1-5" href="#__codelineno-1-5"></a><span class="w"> </span><span class="c1">// 配列の最初のk個の要素をヒープに入力</span>
<a id="__codelineno-1-5" name="__codelineno-1-5" href="#__codelineno-1-5"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-1-6" name="__codelineno-1-6" href="#__codelineno-1-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-7" name="__codelineno-1-7" href="#__codelineno-1-7"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">push</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-1-8" name="__codelineno-1-8" href="#__codelineno-1-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-1-9" name="__codelineno-1-9" href="#__codelineno-1-9"></a><span class="w"> </span><span class="c1">// k+1番目の要素から、ヒープの長さをkに保つ</span>
<a id="__codelineno-1-9" name="__codelineno-1-9" href="#__codelineno-1-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-1-10" name="__codelineno-1-10" href="#__codelineno-1-10"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">size</span><span class="p">();</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-11" name="__codelineno-1-11" href="#__codelineno-1-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭要素より大きい場合、ヒープ先頭要素を削除し、現在の要素をヒープに入力</span>
<a id="__codelineno-1-11" name="__codelineno-1-11" href="#__codelineno-1-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-1-12" name="__codelineno-1-12" href="#__codelineno-1-12"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">top</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-13" name="__codelineno-1-13" href="#__codelineno-1-13"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">pop</span><span class="p">();</span>
<a id="__codelineno-1-14" name="__codelineno-1-14" href="#__codelineno-1-14"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">push</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
@@ -4481,17 +4481,17 @@
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.java</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="cm">/* ヒープを使用して配列の最大 k 個の要素を検索 */</span>
<div class="highlight"><span class="filename">top_k.java</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="cm">/* ヒープに基づいて配列の最大 k 個の要素を探す */</span>
<a id="__codelineno-2-2" name="__codelineno-2-2" href="#__codelineno-2-2"></a><span class="n">Queue</span><span class="o">&lt;</span><span class="n">Integer</span><span class="o">&gt;</span><span class="w"> </span><span class="nf">topKHeap</span><span class="p">(</span><span class="kt">int</span><span class="o">[]</span><span class="w"> </span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-2-3" name="__codelineno-2-3" href="#__codelineno-2-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化</span>
<a id="__codelineno-2-4" name="__codelineno-2-4" href="#__codelineno-2-4"></a><span class="w"> </span><span class="n">Queue</span><span class="o">&lt;</span><span class="n">Integer</span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">PriorityQueue</span><span class="o">&lt;</span><span class="n">Integer</span><span class="o">&gt;</span><span class="p">();</span>
<a id="__codelineno-2-5" name="__codelineno-2-5" href="#__codelineno-2-5"></a><span class="w"> </span><span class="c1">// 配列の最初の k 個の要素をヒープに入力</span>
<a id="__codelineno-2-5" name="__codelineno-2-5" href="#__codelineno-2-5"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-2-6" name="__codelineno-2-6" href="#__codelineno-2-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-2-7" name="__codelineno-2-7" href="#__codelineno-2-7"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">offer</span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">);</span>
<a id="__codelineno-2-8" name="__codelineno-2-8" href="#__codelineno-2-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-2-9" name="__codelineno-2-9" href="#__codelineno-2-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から、ヒープの長さを k に保つ</span>
<a id="__codelineno-2-9" name="__codelineno-2-9" href="#__codelineno-2-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープを k に保つ</span>
<a id="__codelineno-2-10" name="__codelineno-2-10" href="#__codelineno-2-10"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="na">length</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-2-11" name="__codelineno-2-11" href="#__codelineno-2-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭要素より大きい場合、ヒープ先頭要素を削除し、現在の要素をヒープに入力</span>
<a id="__codelineno-2-11" name="__codelineno-2-11" href="#__codelineno-2-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-2-12" name="__codelineno-2-12" href="#__codelineno-2-12"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">peek</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-2-13" name="__codelineno-2-13" href="#__codelineno-2-13"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">poll</span><span class="p">();</span>
<a id="__codelineno-2-14" name="__codelineno-2-14" href="#__codelineno-2-14"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">offer</span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">);</span>
@@ -4502,73 +4502,316 @@
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.cs</span><pre><span></span><code><a id="__codelineno-3-1" name="__codelineno-3-1" href="#__codelineno-3-1"></a><span class="na">[class]</span><span class="p">{</span><span class="n">top_k</span><span class="p">}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">TopKHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.cs</span><pre><span></span><code><a id="__codelineno-3-1" name="__codelineno-3-1" href="#__codelineno-3-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-3-2" name="__codelineno-3-2" href="#__codelineno-3-2"></a><span class="n">PriorityQueue</span><span class="o">&lt;</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">TopKHeap</span><span class="p">(</span><span class="kt">int</span><span class="p">[]</span><span class="w"> </span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-3-3" name="__codelineno-3-3" href="#__codelineno-3-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化</span>
<a id="__codelineno-3-4" name="__codelineno-3-4" href="#__codelineno-3-4"></a><span class="w"> </span><span class="n">PriorityQueue</span><span class="o">&lt;</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="p">();</span>
<a id="__codelineno-3-5" name="__codelineno-3-5" href="#__codelineno-3-5"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-3-6" name="__codelineno-3-6" href="#__codelineno-3-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-3-7" name="__codelineno-3-7" href="#__codelineno-3-7"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">Enqueue</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">],</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-3-8" name="__codelineno-3-8" href="#__codelineno-3-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-3-9" name="__codelineno-3-9" href="#__codelineno-3-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-3-10" name="__codelineno-3-10" href="#__codelineno-3-10"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">Length</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-3-11" name="__codelineno-3-11" href="#__codelineno-3-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-3-12" name="__codelineno-3-12" href="#__codelineno-3-12"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">Peek</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-3-13" name="__codelineno-3-13" href="#__codelineno-3-13"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">Dequeue</span><span class="p">();</span>
<a id="__codelineno-3-14" name="__codelineno-3-14" href="#__codelineno-3-14"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">Enqueue</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">],</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-3-15" name="__codelineno-3-15" href="#__codelineno-3-15"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-3-16" name="__codelineno-3-16" href="#__codelineno-3-16"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-3-17" name="__codelineno-3-17" href="#__codelineno-3-17"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">heap</span><span class="p">;</span>
<a id="__codelineno-3-18" name="__codelineno-3-18" href="#__codelineno-3-18"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.go</span><pre><span></span><code><a id="__codelineno-4-1" name="__codelineno-4-1" href="#__codelineno-4-1"></a><span class="p">[</span><span class="nx">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="kd">func</span><span class="p">]{</span><span class="nx">topKHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.go</span><pre><span></span><code><a id="__codelineno-4-1" name="__codelineno-4-1" href="#__codelineno-4-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-4-2" name="__codelineno-4-2" href="#__codelineno-4-2"></a><span class="kd">func</span><span class="w"> </span><span class="nx">topKHeap</span><span class="p">(</span><span class="nx">nums</span><span class="w"> </span><span class="p">[]</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="nx">k</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="o">*</span><span class="nx">minHeap</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-4-3" name="__codelineno-4-3" href="#__codelineno-4-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化</span>
<a id="__codelineno-4-4" name="__codelineno-4-4" href="#__codelineno-4-4"></a><span class="w"> </span><span class="nx">h</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">minHeap</span><span class="p">{}</span>
<a id="__codelineno-4-5" name="__codelineno-4-5" href="#__codelineno-4-5"></a><span class="w"> </span><span class="nx">heap</span><span class="p">.</span><span class="nx">Init</span><span class="p">(</span><span class="nx">h</span><span class="p">)</span>
<a id="__codelineno-4-6" name="__codelineno-4-6" href="#__codelineno-4-6"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-4-7" name="__codelineno-4-7" href="#__codelineno-4-7"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="p">&lt;</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-4-8" name="__codelineno-4-8" href="#__codelineno-4-8"></a><span class="w"> </span><span class="nx">heap</span><span class="p">.</span><span class="nx">Push</span><span class="p">(</span><span class="nx">h</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">])</span>
<a id="__codelineno-4-9" name="__codelineno-4-9" href="#__codelineno-4-9"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-4-10" name="__codelineno-4-10" href="#__codelineno-4-10"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-4-11" name="__codelineno-4-11" href="#__codelineno-4-11"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="p">&lt;</span><span class="w"> </span><span class="nb">len</span><span class="p">(</span><span class="nx">nums</span><span class="p">);</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-4-12" name="__codelineno-4-12" href="#__codelineno-4-12"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-4-13" name="__codelineno-4-13" href="#__codelineno-4-13"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="nx">h</span><span class="p">.</span><span class="nx">Top</span><span class="p">().(</span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-4-14" name="__codelineno-4-14" href="#__codelineno-4-14"></a><span class="w"> </span><span class="nx">heap</span><span class="p">.</span><span class="nx">Pop</span><span class="p">(</span><span class="nx">h</span><span class="p">)</span>
<a id="__codelineno-4-15" name="__codelineno-4-15" href="#__codelineno-4-15"></a><span class="w"> </span><span class="nx">heap</span><span class="p">.</span><span class="nx">Push</span><span class="p">(</span><span class="nx">h</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">])</span>
<a id="__codelineno-4-16" name="__codelineno-4-16" href="#__codelineno-4-16"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-4-17" name="__codelineno-4-17" href="#__codelineno-4-17"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-4-18" name="__codelineno-4-18" href="#__codelineno-4-18"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">h</span>
<a id="__codelineno-4-19" name="__codelineno-4-19" href="#__codelineno-4-19"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.swift</span><pre><span></span><code><a id="__codelineno-5-1" name="__codelineno-5-1" href="#__codelineno-5-1"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="kd">func</span><span class="p">]{</span><span class="n">topKHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.swift</span><pre><span></span><code><a id="__codelineno-5-1" name="__codelineno-5-1" href="#__codelineno-5-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-5-2" name="__codelineno-5-2" href="#__codelineno-5-2"></a><span class="kd">func</span><span class="w"> </span><span class="nf">topKHeap</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span><span class="w"> </span><span class="p">[</span><span class="nb">Int</span><span class="p">],</span><span class="w"> </span><span class="n">k</span><span class="p">:</span><span class="w"> </span><span class="nb">Int</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="p">[</span><span class="nb">Int</span><span class="p">]</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-5-3" name="__codelineno-5-3" href="#__codelineno-5-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化し、先頭 k 個の要素でヒープを構築する</span>
<a id="__codelineno-5-4" name="__codelineno-5-4" href="#__codelineno-5-4"></a><span class="w"> </span><span class="kd">var</span><span class="w"> </span><span class="nv">heap</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">Heap</span><span class="p">(</span><span class="n">nums</span><span class="p">.</span><span class="kr">prefix</span><span class="p">(</span><span class="n">k</span><span class="p">))</span>
<a id="__codelineno-5-5" name="__codelineno-5-5" href="#__codelineno-5-5"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-5-6" name="__codelineno-5-6" href="#__codelineno-5-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="bp">indices</span><span class="p">.</span><span class="bp">dropFirst</span><span class="p">(</span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-5-7" name="__codelineno-5-7" href="#__codelineno-5-7"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-5-8" name="__codelineno-5-8" href="#__codelineno-5-8"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="bp">min</span><span class="p">()</span><span class="o">!</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-5-9" name="__codelineno-5-9" href="#__codelineno-5-9"></a><span class="w"> </span><span class="kc">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">removeMin</span><span class="p">()</span>
<a id="__codelineno-5-10" name="__codelineno-5-10" href="#__codelineno-5-10"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="bp">insert</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
<a id="__codelineno-5-11" name="__codelineno-5-11" href="#__codelineno-5-11"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-5-12" name="__codelineno-5-12" href="#__codelineno-5-12"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-5-13" name="__codelineno-5-13" href="#__codelineno-5-13"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">unordered</span>
<a id="__codelineno-5-14" name="__codelineno-5-14" href="#__codelineno-5-14"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.js</span><pre><span></span><code><a id="__codelineno-6-1" name="__codelineno-6-1" href="#__codelineno-6-1"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">pushMinHeap</span><span class="p">}</span>
<a id="__codelineno-6-2" name="__codelineno-6-2" href="#__codelineno-6-2"></a>
<a id="__codelineno-6-3" name="__codelineno-6-3" href="#__codelineno-6-3"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">popMinHeap</span><span class="p">}</span>
<a id="__codelineno-6-4" name="__codelineno-6-4" href="#__codelineno-6-4"></a>
<a id="__codelineno-6-5" name="__codelineno-6-5" href="#__codelineno-6-5"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">peekMinHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.js</span><pre><span></span><code><a id="__codelineno-6-1" name="__codelineno-6-1" href="#__codelineno-6-1"></a><span class="cm">/* 要素をヒープに追加 */</span>
<a id="__codelineno-6-2" name="__codelineno-6-2" href="#__codelineno-6-2"></a><span class="kd">function</span><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">val</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-3" name="__codelineno-6-3" href="#__codelineno-6-3"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-6-4" name="__codelineno-6-4" href="#__codelineno-6-4"></a><span class="w"> </span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">push</span><span class="p">(</span><span class="o">-</span><span class="nx">val</span><span class="p">);</span>
<a id="__codelineno-6-5" name="__codelineno-6-5" href="#__codelineno-6-5"></a><span class="p">}</span>
<a id="__codelineno-6-6" name="__codelineno-6-6" href="#__codelineno-6-6"></a>
<a id="__codelineno-6-7" name="__codelineno-6-7" href="#__codelineno-6-7"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">getMinHeap</span><span class="p">}</span>
<a id="__codelineno-6-8" name="__codelineno-6-8" href="#__codelineno-6-8"></a>
<a id="__codelineno-6-9" name="__codelineno-6-9" href="#__codelineno-6-9"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">topKHeap</span><span class="p">}</span>
<a id="__codelineno-6-7" name="__codelineno-6-7" href="#__codelineno-6-7"></a><span class="cm">/* 要素をヒープから取り出す */</span>
<a id="__codelineno-6-8" name="__codelineno-6-8" href="#__codelineno-6-8"></a><span class="kd">function</span><span class="w"> </span><span class="nx">popMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-9" name="__codelineno-6-9" href="#__codelineno-6-9"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-6-10" name="__codelineno-6-10" href="#__codelineno-6-10"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">pop</span><span class="p">();</span>
<a id="__codelineno-6-11" name="__codelineno-6-11" href="#__codelineno-6-11"></a><span class="p">}</span>
<a id="__codelineno-6-12" name="__codelineno-6-12" href="#__codelineno-6-12"></a>
<a id="__codelineno-6-13" name="__codelineno-6-13" href="#__codelineno-6-13"></a><span class="cm">/* ヒープ先頭要素にアクセス */</span>
<a id="__codelineno-6-14" name="__codelineno-6-14" href="#__codelineno-6-14"></a><span class="kd">function</span><span class="w"> </span><span class="nx">peekMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-15" name="__codelineno-6-15" href="#__codelineno-6-15"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-6-16" name="__codelineno-6-16" href="#__codelineno-6-16"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">peek</span><span class="p">();</span>
<a id="__codelineno-6-17" name="__codelineno-6-17" href="#__codelineno-6-17"></a><span class="p">}</span>
<a id="__codelineno-6-18" name="__codelineno-6-18" href="#__codelineno-6-18"></a>
<a id="__codelineno-6-19" name="__codelineno-6-19" href="#__codelineno-6-19"></a><span class="cm">/* ヒープから要素を取り出す */</span>
<a id="__codelineno-6-20" name="__codelineno-6-20" href="#__codelineno-6-20"></a><span class="kd">function</span><span class="w"> </span><span class="nx">getMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-21" name="__codelineno-6-21" href="#__codelineno-6-21"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-6-22" name="__codelineno-6-22" href="#__codelineno-6-22"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">getMaxHeap</span><span class="p">().</span><span class="nx">map</span><span class="p">((</span><span class="nx">num</span><span class="p">)</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="o">-</span><span class="nx">num</span><span class="p">);</span>
<a id="__codelineno-6-23" name="__codelineno-6-23" href="#__codelineno-6-23"></a><span class="p">}</span>
<a id="__codelineno-6-24" name="__codelineno-6-24" href="#__codelineno-6-24"></a>
<a id="__codelineno-6-25" name="__codelineno-6-25" href="#__codelineno-6-25"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-6-26" name="__codelineno-6-26" href="#__codelineno-6-26"></a><span class="kd">function</span><span class="w"> </span><span class="nx">topKHeap</span><span class="p">(</span><span class="nx">nums</span><span class="p">,</span><span class="w"> </span><span class="nx">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-27" name="__codelineno-6-27" href="#__codelineno-6-27"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化する</span>
<a id="__codelineno-6-28" name="__codelineno-6-28" href="#__codelineno-6-28"></a><span class="w"> </span><span class="c1">// 注意: ヒープ内の全要素を反転し、最大ヒープで最小ヒープをシミュレートする</span>
<a id="__codelineno-6-29" name="__codelineno-6-29" href="#__codelineno-6-29"></a><span class="w"> </span><span class="kd">const</span><span class="w"> </span><span class="nx">maxHeap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nx">MaxHeap</span><span class="p">([]);</span>
<a id="__codelineno-6-30" name="__codelineno-6-30" href="#__codelineno-6-30"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-6-31" name="__codelineno-6-31" href="#__codelineno-6-31"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-32" name="__codelineno-6-32" href="#__codelineno-6-32"></a><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]);</span>
<a id="__codelineno-6-33" name="__codelineno-6-33" href="#__codelineno-6-33"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-6-34" name="__codelineno-6-34" href="#__codelineno-6-34"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-6-35" name="__codelineno-6-35" href="#__codelineno-6-35"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">nums</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-36" name="__codelineno-6-36" href="#__codelineno-6-36"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-6-37" name="__codelineno-6-37" href="#__codelineno-6-37"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="nx">peekMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">))</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-6-38" name="__codelineno-6-38" href="#__codelineno-6-38"></a><span class="w"> </span><span class="nx">popMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">);</span>
<a id="__codelineno-6-39" name="__codelineno-6-39" href="#__codelineno-6-39"></a><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]);</span>
<a id="__codelineno-6-40" name="__codelineno-6-40" href="#__codelineno-6-40"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-6-41" name="__codelineno-6-41" href="#__codelineno-6-41"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-6-42" name="__codelineno-6-42" href="#__codelineno-6-42"></a><span class="w"> </span><span class="c1">// ヒープ内の要素を返す</span>
<a id="__codelineno-6-43" name="__codelineno-6-43" href="#__codelineno-6-43"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">getMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">);</span>
<a id="__codelineno-6-44" name="__codelineno-6-44" href="#__codelineno-6-44"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.ts</span><pre><span></span><code><a id="__codelineno-7-1" name="__codelineno-7-1" href="#__codelineno-7-1"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">pushMinHeap</span><span class="p">}</span>
<a id="__codelineno-7-2" name="__codelineno-7-2" href="#__codelineno-7-2"></a>
<a id="__codelineno-7-3" name="__codelineno-7-3" href="#__codelineno-7-3"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">popMinHeap</span><span class="p">}</span>
<a id="__codelineno-7-4" name="__codelineno-7-4" href="#__codelineno-7-4"></a>
<a id="__codelineno-7-5" name="__codelineno-7-5" href="#__codelineno-7-5"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">peekMinHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.ts</span><pre><span></span><code><a id="__codelineno-7-1" name="__codelineno-7-1" href="#__codelineno-7-1"></a><span class="cm">/* 要素をヒープに追加 */</span>
<a id="__codelineno-7-2" name="__codelineno-7-2" href="#__codelineno-7-2"></a><span class="kd">function</span><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="o">:</span><span class="w"> </span><span class="kt">MaxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">val</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="ow">void</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-3" name="__codelineno-7-3" href="#__codelineno-7-3"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-7-4" name="__codelineno-7-4" href="#__codelineno-7-4"></a><span class="w"> </span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">push</span><span class="p">(</span><span class="o">-</span><span class="nx">val</span><span class="p">);</span>
<a id="__codelineno-7-5" name="__codelineno-7-5" href="#__codelineno-7-5"></a><span class="p">}</span>
<a id="__codelineno-7-6" name="__codelineno-7-6" href="#__codelineno-7-6"></a>
<a id="__codelineno-7-7" name="__codelineno-7-7" href="#__codelineno-7-7"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">getMinHeap</span><span class="p">}</span>
<a id="__codelineno-7-8" name="__codelineno-7-8" href="#__codelineno-7-8"></a>
<a id="__codelineno-7-9" name="__codelineno-7-9" href="#__codelineno-7-9"></a><span class="p">[</span><span class="kd">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="nx">func</span><span class="p">]{</span><span class="nx">topKHeap</span><span class="p">}</span>
<a id="__codelineno-7-7" name="__codelineno-7-7" href="#__codelineno-7-7"></a><span class="cm">/* 要素をヒープから取り出す */</span>
<a id="__codelineno-7-8" name="__codelineno-7-8" href="#__codelineno-7-8"></a><span class="kd">function</span><span class="w"> </span><span class="nx">popMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="o">:</span><span class="w"> </span><span class="kt">MaxHeap</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-9" name="__codelineno-7-9" href="#__codelineno-7-9"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-7-10" name="__codelineno-7-10" href="#__codelineno-7-10"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">pop</span><span class="p">();</span>
<a id="__codelineno-7-11" name="__codelineno-7-11" href="#__codelineno-7-11"></a><span class="p">}</span>
<a id="__codelineno-7-12" name="__codelineno-7-12" href="#__codelineno-7-12"></a>
<a id="__codelineno-7-13" name="__codelineno-7-13" href="#__codelineno-7-13"></a><span class="cm">/* ヒープ先頭要素にアクセス */</span>
<a id="__codelineno-7-14" name="__codelineno-7-14" href="#__codelineno-7-14"></a><span class="kd">function</span><span class="w"> </span><span class="nx">peekMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="o">:</span><span class="w"> </span><span class="kt">MaxHeap</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-15" name="__codelineno-7-15" href="#__codelineno-7-15"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-7-16" name="__codelineno-7-16" href="#__codelineno-7-16"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">peek</span><span class="p">();</span>
<a id="__codelineno-7-17" name="__codelineno-7-17" href="#__codelineno-7-17"></a><span class="p">}</span>
<a id="__codelineno-7-18" name="__codelineno-7-18" href="#__codelineno-7-18"></a>
<a id="__codelineno-7-19" name="__codelineno-7-19" href="#__codelineno-7-19"></a><span class="cm">/* ヒープから要素を取り出す */</span>
<a id="__codelineno-7-20" name="__codelineno-7-20" href="#__codelineno-7-20"></a><span class="kd">function</span><span class="w"> </span><span class="nx">getMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="o">:</span><span class="w"> </span><span class="kt">MaxHeap</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">[]</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-21" name="__codelineno-7-21" href="#__codelineno-7-21"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-7-22" name="__codelineno-7-22" href="#__codelineno-7-22"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">maxHeap</span><span class="p">.</span><span class="nx">getMaxHeap</span><span class="p">().</span><span class="nx">map</span><span class="p">((</span><span class="nx">num</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">)</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="o">-</span><span class="nx">num</span><span class="p">);</span>
<a id="__codelineno-7-23" name="__codelineno-7-23" href="#__codelineno-7-23"></a><span class="p">}</span>
<a id="__codelineno-7-24" name="__codelineno-7-24" href="#__codelineno-7-24"></a>
<a id="__codelineno-7-25" name="__codelineno-7-25" href="#__codelineno-7-25"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-7-26" name="__codelineno-7-26" href="#__codelineno-7-26"></a><span class="kd">function</span><span class="w"> </span><span class="nx">topKHeap</span><span class="p">(</span><span class="nx">nums</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">[],</span><span class="w"> </span><span class="nx">k</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="p">[]</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-27" name="__codelineno-7-27" href="#__codelineno-7-27"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化する</span>
<a id="__codelineno-7-28" name="__codelineno-7-28" href="#__codelineno-7-28"></a><span class="w"> </span><span class="c1">// 注意: ヒープ内の全要素を反転し、最大ヒープで最小ヒープをシミュレートする</span>
<a id="__codelineno-7-29" name="__codelineno-7-29" href="#__codelineno-7-29"></a><span class="w"> </span><span class="kd">const</span><span class="w"> </span><span class="nx">maxHeap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nx">MaxHeap</span><span class="p">([]);</span>
<a id="__codelineno-7-30" name="__codelineno-7-30" href="#__codelineno-7-30"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-7-31" name="__codelineno-7-31" href="#__codelineno-7-31"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-32" name="__codelineno-7-32" href="#__codelineno-7-32"></a><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]);</span>
<a id="__codelineno-7-33" name="__codelineno-7-33" href="#__codelineno-7-33"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-7-34" name="__codelineno-7-34" href="#__codelineno-7-34"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-7-35" name="__codelineno-7-35" href="#__codelineno-7-35"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nx">k</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">nums</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-36" name="__codelineno-7-36" href="#__codelineno-7-36"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-7-37" name="__codelineno-7-37" href="#__codelineno-7-37"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="nx">peekMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">))</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-7-38" name="__codelineno-7-38" href="#__codelineno-7-38"></a><span class="w"> </span><span class="nx">popMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">);</span>
<a id="__codelineno-7-39" name="__codelineno-7-39" href="#__codelineno-7-39"></a><span class="w"> </span><span class="nx">pushMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="nx">nums</span><span class="p">[</span><span class="nx">i</span><span class="p">]);</span>
<a id="__codelineno-7-40" name="__codelineno-7-40" href="#__codelineno-7-40"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-7-41" name="__codelineno-7-41" href="#__codelineno-7-41"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-7-42" name="__codelineno-7-42" href="#__codelineno-7-42"></a><span class="w"> </span><span class="c1">// ヒープ内の要素を返す</span>
<a id="__codelineno-7-43" name="__codelineno-7-43" href="#__codelineno-7-43"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">getMinHeap</span><span class="p">(</span><span class="nx">maxHeap</span><span class="p">);</span>
<a id="__codelineno-7-44" name="__codelineno-7-44" href="#__codelineno-7-44"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.dart</span><pre><span></span><code><a id="__codelineno-8-1" name="__codelineno-8-1" href="#__codelineno-8-1"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">topKHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.dart</span><pre><span></span><code><a id="__codelineno-8-1" name="__codelineno-8-1" href="#__codelineno-8-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-8-2" name="__codelineno-8-2" href="#__codelineno-8-2"></a><span class="n">MinHeap</span><span class="w"> </span><span class="n">topKHeap</span><span class="p">(</span><span class="n">List</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-8-3" name="__codelineno-8-3" href="#__codelineno-8-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化し、配列の先頭 k 個の要素をヒープに入れる</span>
<a id="__codelineno-8-4" name="__codelineno-8-4" href="#__codelineno-8-4"></a><span class="w"> </span><span class="n">MinHeap</span><span class="w"> </span><span class="n">heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">MinHeap</span><span class="p">(</span><span class="n">nums</span><span class="p">.</span><span class="n">sublist</span><span class="p">(</span><span class="m">0</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="p">));</span>
<a id="__codelineno-8-5" name="__codelineno-8-5" href="#__codelineno-8-5"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-8-6" name="__codelineno-8-6" href="#__codelineno-8-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">length</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-8-7" name="__codelineno-8-7" href="#__codelineno-8-7"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-8-8" name="__codelineno-8-8" href="#__codelineno-8-8"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">peek</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-8-9" name="__codelineno-8-9" href="#__codelineno-8-9"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">pop</span><span class="p">();</span>
<a id="__codelineno-8-10" name="__codelineno-8-10" href="#__codelineno-8-10"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">push</span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-8-11" name="__codelineno-8-11" href="#__codelineno-8-11"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-8-12" name="__codelineno-8-12" href="#__codelineno-8-12"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-8-13" name="__codelineno-8-13" href="#__codelineno-8-13"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">heap</span><span class="p">;</span>
<a id="__codelineno-8-14" name="__codelineno-8-14" href="#__codelineno-8-14"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.rs</span><pre><span></span><code><a id="__codelineno-9-1" name="__codelineno-9-1" href="#__codelineno-9-1"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">top_k_heap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.rs</span><pre><span></span><code><a id="__codelineno-9-1" name="__codelineno-9-1" href="#__codelineno-9-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-9-2" name="__codelineno-9-2" href="#__codelineno-9-2"></a><span class="k">fn</span><span class="w"> </span><span class="nf">top_k_heap</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span><span class="w"> </span><span class="nb">Vec</span><span class="o">&lt;</span><span class="kt">i32</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="p">:</span><span class="w"> </span><span class="kt">usize</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="nc">BinaryHeap</span><span class="o">&lt;</span><span class="n">Reverse</span><span class="o">&lt;</span><span class="kt">i32</span><span class="o">&gt;&gt;</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-9-3" name="__codelineno-9-3" href="#__codelineno-9-3"></a><span class="w"> </span><span class="c1">// BinaryHeap は最大ヒープであり、Reverse で要素の順序を反転することで最小ヒープを実現する</span>
<a id="__codelineno-9-4" name="__codelineno-9-4" href="#__codelineno-9-4"></a><span class="w"> </span><span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">BinaryHeap</span><span class="p">::</span><span class="o">&lt;</span><span class="n">Reverse</span><span class="o">&lt;</span><span class="kt">i32</span><span class="o">&gt;&gt;</span><span class="p">::</span><span class="n">new</span><span class="p">();</span>
<a id="__codelineno-9-5" name="__codelineno-9-5" href="#__codelineno-9-5"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-9-6" name="__codelineno-9-6" href="#__codelineno-9-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="o">&amp;</span><span class="n">num</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">iter</span><span class="p">().</span><span class="n">take</span><span class="p">(</span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-9-7" name="__codelineno-9-7" href="#__codelineno-9-7"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">push</span><span class="p">(</span><span class="n">Reverse</span><span class="p">(</span><span class="n">num</span><span class="p">));</span>
<a id="__codelineno-9-8" name="__codelineno-9-8" href="#__codelineno-9-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-9-9" name="__codelineno-9-9" href="#__codelineno-9-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-9-10" name="__codelineno-9-10" href="#__codelineno-9-10"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="o">&amp;</span><span class="n">num</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">iter</span><span class="p">().</span><span class="n">skip</span><span class="p">(</span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-9-11" name="__codelineno-9-11" href="#__codelineno-9-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-9-12" name="__codelineno-9-12" href="#__codelineno-9-12"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">peek</span><span class="p">().</span><span class="n">unwrap</span><span class="p">().</span><span class="mi">0</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-9-13" name="__codelineno-9-13" href="#__codelineno-9-13"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">pop</span><span class="p">();</span>
<a id="__codelineno-9-14" name="__codelineno-9-14" href="#__codelineno-9-14"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="n">push</span><span class="p">(</span><span class="n">Reverse</span><span class="p">(</span><span class="n">num</span><span class="p">));</span>
<a id="__codelineno-9-15" name="__codelineno-9-15" href="#__codelineno-9-15"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-9-16" name="__codelineno-9-16" href="#__codelineno-9-16"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-9-17" name="__codelineno-9-17" href="#__codelineno-9-17"></a><span class="w"> </span><span class="n">heap</span>
<a id="__codelineno-9-18" name="__codelineno-9-18" href="#__codelineno-9-18"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.c</span><pre><span></span><code><a id="__codelineno-10-1" name="__codelineno-10-1" href="#__codelineno-10-1"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">pushMinHeap</span><span class="p">}</span>
<a id="__codelineno-10-2" name="__codelineno-10-2" href="#__codelineno-10-2"></a>
<a id="__codelineno-10-3" name="__codelineno-10-3" href="#__codelineno-10-3"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">popMinHeap</span><span class="p">}</span>
<a id="__codelineno-10-4" name="__codelineno-10-4" href="#__codelineno-10-4"></a>
<a id="__codelineno-10-5" name="__codelineno-10-5" href="#__codelineno-10-5"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">peekMinHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.c</span><pre><span></span><code><a id="__codelineno-10-1" name="__codelineno-10-1" href="#__codelineno-10-1"></a><span class="cm">/* 要素をヒープに追加 */</span>
<a id="__codelineno-10-2" name="__codelineno-10-2" href="#__codelineno-10-2"></a><span class="kt">void</span><span class="w"> </span><span class="nf">pushMinHeap</span><span class="p">(</span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">val</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-3" name="__codelineno-10-3" href="#__codelineno-10-3"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-10-4" name="__codelineno-10-4" href="#__codelineno-10-4"></a><span class="w"> </span><span class="n">push</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="o">-</span><span class="n">val</span><span class="p">);</span>
<a id="__codelineno-10-5" name="__codelineno-10-5" href="#__codelineno-10-5"></a><span class="p">}</span>
<a id="__codelineno-10-6" name="__codelineno-10-6" href="#__codelineno-10-6"></a>
<a id="__codelineno-10-7" name="__codelineno-10-7" href="#__codelineno-10-7"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">getMinHeap</span><span class="p">}</span>
<a id="__codelineno-10-8" name="__codelineno-10-8" href="#__codelineno-10-8"></a>
<a id="__codelineno-10-9" name="__codelineno-10-9" href="#__codelineno-10-9"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">topKHeap</span><span class="p">}</span>
<a id="__codelineno-10-7" name="__codelineno-10-7" href="#__codelineno-10-7"></a><span class="cm">/* 要素をヒープから取り出す */</span>
<a id="__codelineno-10-8" name="__codelineno-10-8" href="#__codelineno-10-8"></a><span class="kt">int</span><span class="w"> </span><span class="nf">popMinHeap</span><span class="p">(</span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-9" name="__codelineno-10-9" href="#__codelineno-10-9"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-10-10" name="__codelineno-10-10" href="#__codelineno-10-10"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="n">pop</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">);</span>
<a id="__codelineno-10-11" name="__codelineno-10-11" href="#__codelineno-10-11"></a><span class="p">}</span>
<a id="__codelineno-10-12" name="__codelineno-10-12" href="#__codelineno-10-12"></a>
<a id="__codelineno-10-13" name="__codelineno-10-13" href="#__codelineno-10-13"></a><span class="cm">/* ヒープ先頭要素にアクセス */</span>
<a id="__codelineno-10-14" name="__codelineno-10-14" href="#__codelineno-10-14"></a><span class="kt">int</span><span class="w"> </span><span class="nf">peekMinHeap</span><span class="p">(</span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-15" name="__codelineno-10-15" href="#__codelineno-10-15"></a><span class="w"> </span><span class="c1">// 要素を反転する</span>
<a id="__codelineno-10-16" name="__codelineno-10-16" href="#__codelineno-10-16"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="o">-</span><span class="n">peek</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">);</span>
<a id="__codelineno-10-17" name="__codelineno-10-17" href="#__codelineno-10-17"></a><span class="p">}</span>
<a id="__codelineno-10-18" name="__codelineno-10-18" href="#__codelineno-10-18"></a>
<a id="__codelineno-10-19" name="__codelineno-10-19" href="#__codelineno-10-19"></a><span class="cm">/* ヒープから要素を取り出す */</span>
<a id="__codelineno-10-20" name="__codelineno-10-20" href="#__codelineno-10-20"></a><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="nf">getMinHeap</span><span class="p">(</span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-21" name="__codelineno-10-21" href="#__codelineno-10-21"></a><span class="w"> </span><span class="c1">// ヒープ内のすべての要素を反転して res 配列に格納</span>
<a id="__codelineno-10-22" name="__codelineno-10-22" href="#__codelineno-10-22"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="n">res</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="p">)</span><span class="n">malloc</span><span class="p">(</span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">size</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">sizeof</span><span class="p">(</span><span class="kt">int</span><span class="p">));</span>
<a id="__codelineno-10-23" name="__codelineno-10-23" href="#__codelineno-10-23"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">size</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-24" name="__codelineno-10-24" href="#__codelineno-10-24"></a><span class="w"> </span><span class="n">res</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">-</span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">data</span><span class="p">[</span><span class="n">i</span><span class="p">];</span>
<a id="__codelineno-10-25" name="__codelineno-10-25" href="#__codelineno-10-25"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-10-26" name="__codelineno-10-26" href="#__codelineno-10-26"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">res</span><span class="p">;</span>
<a id="__codelineno-10-27" name="__codelineno-10-27" href="#__codelineno-10-27"></a><span class="p">}</span>
<a id="__codelineno-10-28" name="__codelineno-10-28" href="#__codelineno-10-28"></a>
<a id="__codelineno-10-29" name="__codelineno-10-29" href="#__codelineno-10-29"></a><span class="cm">/* ヒープから要素を取り出す */</span>
<a id="__codelineno-10-30" name="__codelineno-10-30" href="#__codelineno-10-30"></a><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="nf">getMinHeap</span><span class="p">(</span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-31" name="__codelineno-10-31" href="#__codelineno-10-31"></a><span class="w"> </span><span class="c1">// ヒープ内のすべての要素を反転して res 配列に格納</span>
<a id="__codelineno-10-32" name="__codelineno-10-32" href="#__codelineno-10-32"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="n">res</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="p">)</span><span class="n">malloc</span><span class="p">(</span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">size</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">sizeof</span><span class="p">(</span><span class="kt">int</span><span class="p">));</span>
<a id="__codelineno-10-33" name="__codelineno-10-33" href="#__codelineno-10-33"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">size</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-34" name="__codelineno-10-34" href="#__codelineno-10-34"></a><span class="w"> </span><span class="n">res</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">-</span><span class="n">maxHeap</span><span class="o">-&gt;</span><span class="n">data</span><span class="p">[</span><span class="n">i</span><span class="p">];</span>
<a id="__codelineno-10-35" name="__codelineno-10-35" href="#__codelineno-10-35"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-10-36" name="__codelineno-10-36" href="#__codelineno-10-36"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">res</span><span class="p">;</span>
<a id="__codelineno-10-37" name="__codelineno-10-37" href="#__codelineno-10-37"></a><span class="p">}</span>
<a id="__codelineno-10-38" name="__codelineno-10-38" href="#__codelineno-10-38"></a>
<a id="__codelineno-10-39" name="__codelineno-10-39" href="#__codelineno-10-39"></a><span class="c1">// ヒープに基づいて配列中の最大の k 個の要素を求める関数</span>
<a id="__codelineno-10-40" name="__codelineno-10-40" href="#__codelineno-10-40"></a><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="nf">topKHeap</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">sizeNums</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-41" name="__codelineno-10-41" href="#__codelineno-10-41"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化する</span>
<a id="__codelineno-10-42" name="__codelineno-10-42" href="#__codelineno-10-42"></a><span class="w"> </span><span class="c1">// 注意: ヒープ内の全要素を反転し、最大ヒープで最小ヒープをシミュレートする</span>
<a id="__codelineno-10-43" name="__codelineno-10-43" href="#__codelineno-10-43"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="n">empty</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="p">)</span><span class="n">malloc</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span>
<a id="__codelineno-10-44" name="__codelineno-10-44" href="#__codelineno-10-44"></a><span class="w"> </span><span class="n">MaxHeap</span><span class="w"> </span><span class="o">*</span><span class="n">maxHeap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">newMaxHeap</span><span class="p">(</span><span class="n">empty</span><span class="p">,</span><span class="w"> </span><span class="mi">0</span><span class="p">);</span>
<a id="__codelineno-10-45" name="__codelineno-10-45" href="#__codelineno-10-45"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-10-46" name="__codelineno-10-46" href="#__codelineno-10-46"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-47" name="__codelineno-10-47" href="#__codelineno-10-47"></a><span class="w"> </span><span class="n">pushMinHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-10-48" name="__codelineno-10-48" href="#__codelineno-10-48"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-10-49" name="__codelineno-10-49" href="#__codelineno-10-49"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-10-50" name="__codelineno-10-50" href="#__codelineno-10-50"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">sizeNums</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-51" name="__codelineno-10-51" href="#__codelineno-10-51"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-10-52" name="__codelineno-10-52" href="#__codelineno-10-52"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">peekMinHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">))</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-10-53" name="__codelineno-10-53" href="#__codelineno-10-53"></a><span class="w"> </span><span class="n">popMinHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">);</span>
<a id="__codelineno-10-54" name="__codelineno-10-54" href="#__codelineno-10-54"></a><span class="w"> </span><span class="n">pushMinHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">,</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>
<a id="__codelineno-10-55" name="__codelineno-10-55" href="#__codelineno-10-55"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-10-56" name="__codelineno-10-56" href="#__codelineno-10-56"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-10-57" name="__codelineno-10-57" href="#__codelineno-10-57"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="o">*</span><span class="n">res</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">getMinHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">);</span>
<a id="__codelineno-10-58" name="__codelineno-10-58" href="#__codelineno-10-58"></a><span class="w"> </span><span class="c1">// メモリを解放する</span>
<a id="__codelineno-10-59" name="__codelineno-10-59" href="#__codelineno-10-59"></a><span class="w"> </span><span class="n">delMaxHeap</span><span class="p">(</span><span class="n">maxHeap</span><span class="p">);</span>
<a id="__codelineno-10-60" name="__codelineno-10-60" href="#__codelineno-10-60"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">res</span><span class="p">;</span>
<a id="__codelineno-10-61" name="__codelineno-10-61" href="#__codelineno-10-61"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.kt</span><pre><span></span><code><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="o">[</span><span class="n">class</span><span class="o">]</span><span class="p">{}</span><span class="o">-[</span><span class="n">func</span><span class="o">]</span><span class="p">{</span><span class="n">topKHeap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.kt</span><pre><span></span><code><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="cm">/* ヒープに基づいて配列中の最大の k 個の要素を探す */</span>
<a id="__codelineno-11-2" name="__codelineno-11-2" href="#__codelineno-11-2"></a><span class="kd">fun</span><span class="w"> </span><span class="nf">topKHeap</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span><span class="w"> </span><span class="n">IntArray</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="p">:</span><span class="w"> </span><span class="kt">Int</span><span class="p">):</span><span class="w"> </span><span class="n">Queue</span><span class="o">&lt;</span><span class="kt">Int</span><span class="o">&gt;</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-3" name="__codelineno-11-3" href="#__codelineno-11-3"></a><span class="w"> </span><span class="c1">// 最小ヒープを初期化</span>
<a id="__codelineno-11-4" name="__codelineno-11-4" href="#__codelineno-11-4"></a><span class="w"> </span><span class="kd">val</span><span class="w"> </span><span class="nv">heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">PriorityQueue</span><span class="o">&lt;</span><span class="kt">Int</span><span class="o">&gt;</span><span class="p">()</span>
<a id="__codelineno-11-5" name="__codelineno-11-5" href="#__codelineno-11-5"></a><span class="w"> </span><span class="c1">// 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-11-6" name="__codelineno-11-6" href="#__codelineno-11-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0.</span><span class="p">.</span><span class="o">&lt;</span><span class="n">k</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-7" name="__codelineno-11-7" href="#__codelineno-11-7"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">offer</span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">)</span>
<a id="__codelineno-11-8" name="__codelineno-11-8" href="#__codelineno-11-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-9" name="__codelineno-11-9" href="#__codelineno-11-9"></a><span class="w"> </span><span class="c1">// k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-11-10" name="__codelineno-11-10" href="#__codelineno-11-10"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">k</span><span class="p">..</span><span class="o">&lt;</span><span class="n">nums</span><span class="p">.</span><span class="na">size</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-11" name="__codelineno-11-11" href="#__codelineno-11-11"></a><span class="w"> </span><span class="c1">// 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-11-12" name="__codelineno-11-12" href="#__codelineno-11-12"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">peek</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-13" name="__codelineno-11-13" href="#__codelineno-11-13"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">poll</span><span class="p">()</span>
<a id="__codelineno-11-14" name="__codelineno-11-14" href="#__codelineno-11-14"></a><span class="w"> </span><span class="n">heap</span><span class="p">.</span><span class="na">offer</span><span class="p">(</span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">)</span>
<a id="__codelineno-11-15" name="__codelineno-11-15" href="#__codelineno-11-15"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-16" name="__codelineno-11-16" href="#__codelineno-11-16"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-17" name="__codelineno-11-17" href="#__codelineno-11-17"></a><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">heap</span>
<a id="__codelineno-11-18" name="__codelineno-11-18" href="#__codelineno-11-18"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">top_k.rb</span><pre><span></span><code><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="o">[</span><span class="n">class</span><span class="o">]</span><span class="p">{}</span><span class="o">-[</span><span class="n">func</span><span class="o">]</span><span class="p">{</span><span class="n">top_k_heap</span><span class="p">}</span>
<div class="highlight"><span class="filename">top_k.rb</span><pre><span></span><code><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="c1">### ヒープに基づいて配列中の最大 k 個の要素を探す ###</span>
<a id="__codelineno-12-2" name="__codelineno-12-2" href="#__codelineno-12-2"></a><span class="k">def</span><span class="w"> </span><span class="nf">top_k_heap</span><span class="p">(</span><span class="n">nums</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="p">)</span>
<a id="__codelineno-12-3" name="__codelineno-12-3" href="#__codelineno-12-3"></a><span class="w"> </span><span class="c1"># 最小ヒープを初期化する</span>
<a id="__codelineno-12-4" name="__codelineno-12-4" href="#__codelineno-12-4"></a><span class="w"> </span><span class="c1"># 注意: ヒープ内の全要素を反転し、最大ヒープで最小ヒープをシミュレートする</span>
<a id="__codelineno-12-5" name="__codelineno-12-5" href="#__codelineno-12-5"></a><span class="w"> </span><span class="n">max_heap</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="no">MaxHeap</span><span class="o">.</span><span class="n">new</span><span class="p">(</span><span class="o">[]</span><span class="p">)</span>
<a id="__codelineno-12-6" name="__codelineno-12-6" href="#__codelineno-12-6"></a>
<a id="__codelineno-12-7" name="__codelineno-12-7" href="#__codelineno-12-7"></a><span class="w"> </span><span class="c1"># 配列の先頭 k 個の要素をヒープに追加</span>
<a id="__codelineno-12-8" name="__codelineno-12-8" href="#__codelineno-12-8"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="mi">0</span><span class="o">...</span><span class="n">k</span>
<a id="__codelineno-12-9" name="__codelineno-12-9" href="#__codelineno-12-9"></a><span class="w"> </span><span class="n">push_min_heap</span><span class="p">(</span><span class="n">max_heap</span><span class="p">,</span><span class="w"> </span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">)</span>
<a id="__codelineno-12-10" name="__codelineno-12-10" href="#__codelineno-12-10"></a><span class="w"> </span><span class="k">end</span>
<a id="__codelineno-12-11" name="__codelineno-12-11" href="#__codelineno-12-11"></a>
<a id="__codelineno-12-12" name="__codelineno-12-12" href="#__codelineno-12-12"></a><span class="w"> </span><span class="c1"># k+1 番目の要素から開始し、ヒープ長を k に保つ</span>
<a id="__codelineno-12-13" name="__codelineno-12-13" href="#__codelineno-12-13"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">k</span><span class="o">...</span><span class="n">nums</span><span class="o">.</span><span class="n">length</span>
<a id="__codelineno-12-14" name="__codelineno-12-14" href="#__codelineno-12-14"></a><span class="w"> </span><span class="c1"># 現在の要素がヒープ先頭より大きければ、ヒープ先頭を取り出して現在の要素を追加する</span>
<a id="__codelineno-12-15" name="__codelineno-12-15" href="#__codelineno-12-15"></a><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="n">peek_min_heap</span><span class="p">(</span><span class="n">max_heap</span><span class="p">)</span>
<a id="__codelineno-12-16" name="__codelineno-12-16" href="#__codelineno-12-16"></a><span class="w"> </span><span class="n">pop_min_heap</span><span class="p">(</span><span class="n">max_heap</span><span class="p">)</span>
<a id="__codelineno-12-17" name="__codelineno-12-17" href="#__codelineno-12-17"></a><span class="w"> </span><span class="n">push_min_heap</span><span class="p">(</span><span class="n">max_heap</span><span class="p">,</span><span class="w"> </span><span class="n">nums</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="p">)</span>
<a id="__codelineno-12-18" name="__codelineno-12-18" href="#__codelineno-12-18"></a><span class="w"> </span><span class="k">end</span>
<a id="__codelineno-12-19" name="__codelineno-12-19" href="#__codelineno-12-19"></a><span class="w"> </span><span class="k">end</span>
<a id="__codelineno-12-20" name="__codelineno-12-20" href="#__codelineno-12-20"></a>
<a id="__codelineno-12-21" name="__codelineno-12-21" href="#__codelineno-12-21"></a><span class="w"> </span><span class="n">get_min_heap</span><span class="p">(</span><span class="n">max_heap</span><span class="p">)</span>
<a id="__codelineno-12-22" name="__codelineno-12-22" href="#__codelineno-12-22"></a><span class="k">end</span>
</code></pre></div>
</div>
</div>
</div>
<p>合計<span class="arithmatex">\(n\)</span>回のヒープ挿入と削除が実行され、最大ヒープサイズが<span class="arithmatex">\(k\)</span>であるため、時間計算量は<span class="arithmatex">\(O(n \log k)\)</span>です。この方法は非常に効率的で、<span class="arithmatex">\(k\)</span>が小さい場合、時間計算量は<span class="arithmatex">\(O(n)\)</span>に近づき、<span class="arithmatex">\(k\)</span>が大きい場合でも、時間計算量は<span class="arithmatex">\(O(n \log n)\)</span>を超えません。</p>
<p>さらに、この方法は動的データストリームのシナリオに適しています。データを継続的に追加することで、ヒープ内の要素を維持し、最大<span class="arithmatex">\(k\)</span>個の要素の動的更新を実現できます。</p>
<details class="pythontutor">
<summary>コードの可視化</summary>
<p><div style="height: 549px; width: 100%;"><iframe class="pythontutor-iframe" src="https://pythontutor.com/iframe-embed.html#code=import%20heapq%0A%0Adef%20top_k_heap%28nums%3A%20list%5Bint%5D%2C%20k%3A%20int%29%20-%3E%20list%5Bint%5D%3A%0A%20%20%20%20%22%22%22%E3%83%92%E3%83%BC%E3%83%97%E3%81%AB%E5%9F%BA%E3%81%A5%E3%81%84%E3%81%A6%E9%85%8D%E5%88%97%E4%B8%AD%E3%81%AE%E6%9C%80%E5%A4%A7%E3%81%AE%20k%20%E5%80%8B%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E6%8E%A2%E3%81%99%22%22%22%0A%20%20%20%20%23%20%E6%9C%80%E5%B0%8F%E3%83%92%E3%83%BC%E3%83%97%E3%82%92%E5%88%9D%E6%9C%9F%E5%8C%96%0A%20%20%20%20heap%20%3D%20%5B%5D%0A%20%20%20%20%23%20%E9%85%8D%E5%88%97%E3%81%AE%E5%85%88%E9%A0%AD%20k%20%E5%80%8B%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E3%83%92%E3%83%BC%E3%83%97%E3%81%AB%E8%BF%BD%E5%8A%A0%0A%20%20%20%20for%20i%20in%20range%28k%29%3A%0A%20%20%20%20%20%20%20%20heapq.heappush%28heap%2C%20nums%5Bi%5D%29%0A%20%20%20%20%23%20k%2B1%20%E7%95%AA%E7%9B%AE%E3%81%AE%E8%A6%81%E7%B4%A0%E3%81%8B%E3%82%89%E9%96%8B%E5%A7%8B%E3%81%97%E3%80%81%E3%83%92%E3%83%BC%E3%83%97%E9%95%B7%E3%82%92%20k%20%E3%81%AB%E4%BF%9D%E3%81%A4%0A%20%20%20%20for%20i%20in%20range%28k%2C%20len%28nums%29%29%3A%0A%20%20%20%20%20%20%20%20%23%20%E7%8F%BE%E5%9C%A8%E3%81%AE%E8%A6%81%E7%B4%A0%E3%81%8C%E3%83%92%E3%83%BC%E3%83%97%E5%85%88%E9%A0%AD%E3%82%88%E3%82%8A%E5%A4%A7%E3%81%8D%E3%81%91%E3%82%8C%E3%81%B0%E3%80%81%E3%83%92%E3%83%BC%E3%83%97%E5%85%88%E9%A0%AD%E3%82%92%E5%8F%96%E3%82%8A%E5%87%BA%E3%81%97%E3%81%A6%E7%8F%BE%E5%9C%A8%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E8%BF%BD%E5%8A%A0%E3%81%99%E3%82%8B%0A%20%20%20%20%20%20%20%20if%20nums%5Bi%5D%20%3E%20heap%5B0%5D%3A%0A%20%20%20%20%20%20%20%20%20%20%20%20heapq.heappop%28heap%29%0A%20%20%20%20%20%20%20%20%20%20%20%20heapq.heappush%28heap%2C%20nums%5Bi%5D%29%0A%20%20%20%20return%20heap%0A%0Aif%20__name__%20%3D%3D%20%22__main__%22%3A%0A%20%20%20%20nums%20%3D%20%5B1%2C%207%2C%206%2C%203%2C%202%5D%0A%20%20%20%20k%20%3D%203%0A%0A%20%20%20%20res%20%3D%20top_k_heap%28nums%2C%20k%29&codeDivHeight=472&codeDivWidth=350&cumulative=false&curInstr=6&heapPrimitives=nevernest&origin=opt-frontend.js&py=311&rawInputLstJSON=%5B%5D&textReferences=false"> </iframe></div>
<div style="margin-top: 5px;"><a href="https://pythontutor.com/iframe-embed.html#code=import%20heapq%0A%0Adef%20top_k_heap%28nums%3A%20list%5Bint%5D%2C%20k%3A%20int%29%20-%3E%20list%5Bint%5D%3A%0A%20%20%20%20%22%22%22%E3%83%92%E3%83%BC%E3%83%97%E3%81%AB%E5%9F%BA%E3%81%A5%E3%81%84%E3%81%A6%E9%85%8D%E5%88%97%E4%B8%AD%E3%81%AE%E6%9C%80%E5%A4%A7%E3%81%AE%20k%20%E5%80%8B%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E6%8E%A2%E3%81%99%22%22%22%0A%20%20%20%20%23%20%E6%9C%80%E5%B0%8F%E3%83%92%E3%83%BC%E3%83%97%E3%82%92%E5%88%9D%E6%9C%9F%E5%8C%96%0A%20%20%20%20heap%20%3D%20%5B%5D%0A%20%20%20%20%23%20%E9%85%8D%E5%88%97%E3%81%AE%E5%85%88%E9%A0%AD%20k%20%E5%80%8B%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E3%83%92%E3%83%BC%E3%83%97%E3%81%AB%E8%BF%BD%E5%8A%A0%0A%20%20%20%20for%20i%20in%20range%28k%29%3A%0A%20%20%20%20%20%20%20%20heapq.heappush%28heap%2C%20nums%5Bi%5D%29%0A%20%20%20%20%23%20k%2B1%20%E7%95%AA%E7%9B%AE%E3%81%AE%E8%A6%81%E7%B4%A0%E3%81%8B%E3%82%89%E9%96%8B%E5%A7%8B%E3%81%97%E3%80%81%E3%83%92%E3%83%BC%E3%83%97%E9%95%B7%E3%82%92%20k%20%E3%81%AB%E4%BF%9D%E3%81%A4%0A%20%20%20%20for%20i%20in%20range%28k%2C%20len%28nums%29%29%3A%0A%20%20%20%20%20%20%20%20%23%20%E7%8F%BE%E5%9C%A8%E3%81%AE%E8%A6%81%E7%B4%A0%E3%81%8C%E3%83%92%E3%83%BC%E3%83%97%E5%85%88%E9%A0%AD%E3%82%88%E3%82%8A%E5%A4%A7%E3%81%8D%E3%81%91%E3%82%8C%E3%81%B0%E3%80%81%E3%83%92%E3%83%BC%E3%83%97%E5%85%88%E9%A0%AD%E3%82%92%E5%8F%96%E3%82%8A%E5%87%BA%E3%81%97%E3%81%A6%E7%8F%BE%E5%9C%A8%E3%81%AE%E8%A6%81%E7%B4%A0%E3%82%92%E8%BF%BD%E5%8A%A0%E3%81%99%E3%82%8B%0A%20%20%20%20%20%20%20%20if%20nums%5Bi%5D%20%3E%20heap%5B0%5D%3A%0A%20%20%20%20%20%20%20%20%20%20%20%20heapq.heappop%28heap%29%0A%20%20%20%20%20%20%20%20%20%20%20%20heapq.heappush%28heap%2C%20nums%5Bi%5D%29%0A%20%20%20%20return%20heap%0A%0Aif%20__name__%20%3D%3D%20%22__main__%22%3A%0A%20%20%20%20nums%20%3D%20%5B1%2C%207%2C%206%2C%203%2C%202%5D%0A%20%20%20%20k%20%3D%203%0A%0A%20%20%20%20res%20%3D%20top_k_heap%28nums%2C%20k%29&codeDivHeight=800&codeDivWidth=600&cumulative=false&curInstr=6&heapPrimitives=nevernest&origin=opt-frontend.js&py=311&rawInputLstJSON=%5B%5D&textReferences=false" target="_blank" rel="noopener noreferrer">全画面で見る &gt;</a></div></p>
</details>
<p>合計で <span class="arithmatex">\(n\)</span> 回のヒープ挿入と取り出しを行い、ヒープの最大長は <span class="arithmatex">\(k\)</span> であるため、時間計算量は <span class="arithmatex">\(O(n \log k)\)</span> です。この方法は非常に効率が高く、<span class="arithmatex">\(k\)</span> が小さいときは時間計算量が <span class="arithmatex">\(O(n)\)</span> に近づき、<span class="arithmatex">\(k\)</span> が大きいときでも <span class="arithmatex">\(O(n \log n)\)</span> を超えることはありません。</p>
<p>さらに、この方法は動的データストリームの利用シーンにも適しています。データが継続的に追加される場合でも、ヒープ内の要素を保ち続けることで、最大の <span class="arithmatex">\(k\)</span> 個の要素を動的に更新できます。</p>
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aria-label="前: 8.2 &amp;nbsp; ヒープ構築操作"
aria-label="前: 8.2 &amp;nbsp; ヒープ構築"
rel="prev"
>
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</span>
<div class="md-ellipsis">
8.2 &nbsp; ヒープ構築操作
8.2 &nbsp; ヒープ構築
</div>
</div>
</a>