Bug fixes and improvements (#1298)

* Fix is_empty() implementation in the stack and queue chapter * Update en/CONTRIBUTING.md * Remove "剩余" from the state definition of knapsack problem * Sync zh and zh-hant versions * Update the stylesheets of code tabs * Fix quick_sort.rb * Fix TS code * Update chapter_paperbook * Upload the manuscript of 0.1 section * Fix binary_tree_dfs.rb * Bug fixes * Update README * Update README * Update README * Update README.md * Update README * Sync zh and zh-hant versions * Bug fixes
2026-09-22 14:26:34 +08:00 · 2024-04-22 02:26:32 +08:00
parent 74f1a63e8c
commit f616dac7da
61 changed files with 1606 additions and 145 deletions
@@ -0,0 +1,147 @@
+=begin
+File: hash_map_open_addressing.rb
+Created Time: 2024-04-13
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative './array_hash_map'
+
+### 開放定址雜湊表 ###
+class HashMapOpenAddressing
+  TOMBSTONE = Pair.new(-1, '-1') # 刪除標記
+
+  ### 建構子 ###
+  def initialize
+    @size = 0 # 鍵值對數量
+    @capacity = 4 # 雜湊表容量
+    @load_thres = 2.0 / 3.0 # 觸發擴容的負載因子閾值
+    @extend_ratio = 2 # 擴容倍數
+    @buckets = Array.new(@capacity) # 桶陣列
+  end
+
+  ### 雜湊函式 ###
+  def hash_func(key)
+    key % @capacity
+  end
+
+  ### 負載因子 ###
+  def load_factor
+    @size / @capacity
+  end
+
+  ### 搜尋 key 對應的桶索引 ###
+  def find_bucket(key)
+    index = hash_func(key)
+    first_tombstone = -1
+    # 線性探查，當遇到空桶時跳出
+    while !@buckets[index].nil?
+      # 若遇到 key ，返回對應的桶索引
+      if @buckets[index].key == key
+        # 若之前遇到了刪除標記，則將鍵值對移動至該索引處
+        if first_tombstone != -1
+          @buckets[first_tombstone] = @buckets[index]
+          @buckets[index] = TOMBSTONE
+          return first_tombstone # 返回移動後的桶索引
+        end
+        return index # 返回桶索引
+      end
+      # 記錄遇到的首個刪除標記
+      first_tombstone = index if first_tombstone == -1 && @buckets[index] == TOMBSTONE
+      # 計算桶索引，越過尾部則返回頭部
+      index = (index + 1) % @capacity
+    end
+    # 若 key 不存在，則返回新增點的索引
+    first_tombstone == -1 ? index : first_tombstone
+  end
+
+  ### 查詢操作 ###
+  def get(key)
+    # 搜尋 key 對應的桶索引
+    index = find_bucket(key)
+    # 若找到鍵值對，則返回對應 val
+    return @buckets[index].val unless [nil, TOMBSTONE].include?(@buckets[index])
+    # 若鍵值對不存在，則返回 nil
+    nil
+  end
+
+  ### 新增操作 ###
+  def put(key, val)
+    # 當負載因子超過閾值時，執行擴容
+    extend if load_factor > @load_thres
+    # 搜尋 key 對應的桶索引
+    index = find_bucket(key)
+    # 若找到鍵值對，則覆蓋 val 開返回
+    unless [nil, TOMBSTONE].include?(@buckets[index])
+      @buckets[index].val = val
+      return
+    end
+    # 若鍵值對不存在，則新增該鍵值對
+    @buckets[index] = Pair.new(key, val)
+    @size += 1
+  end
+
+  ### 刪除操作 ###
+  def remove(key)
+    # 搜尋 key 對應的桶索引
+    index = find_bucket(key)
+    # 若找到鍵值對，則用刪除標記覆蓋它
+    unless [nil, TOMBSTONE].include?(@buckets[index])
+      @buckets[index] = TOMBSTONE
+      @size -= 1
+    end
+  end
+
+  ### 擴容雜湊表 ###
+  def extend
+    # 暫存原雜湊表
+    buckets_tmp = @buckets
+    # 初始化擴容後的新雜湊表
+    @capacity *= @extend_ratio
+    @buckets = Array.new(@capacity)
+    @size = 0
+    # 將鍵值對從原雜湊表搬運至新雜湊表
+    for pair in buckets_tmp
+      put(pair.key, pair.val) unless [nil, TOMBSTONE].include?(pair)
+    end
+  end
+
+  ### 列印雜湊表 ###
+  def print
+    for pair in @buckets
+      if pair.nil?
+        puts "Nil"
+      elsif pair == TOMBSTONE
+        puts "TOMBSTONE"
+      else
+        puts "#{pair.key} -> #{pair.val}"
+      end
+    end
+  end
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # 初始化雜湊表
+  hashmap = HashMapOpenAddressing.new
+
+  # 新增操作
+  # 在雜湊表中新增鍵值對 (key, val)
+  hashmap.put(12836, "小哈")
+  hashmap.put(15937, "小囉")
+  hashmap.put(16750, "小算")
+  hashmap.put(13276, "小法")
+  hashmap.put(10583, "小鴨")
+  puts "\n新增完成後，雜湊表為\nKey -> Value"
+  hashmap.print
+
+  # 查詢操作
+  # 向雜湊表中輸入鍵 key ，得到值 val
+  name = hashmap.get(13276)
+  puts "\n輸入學號 13276 ，查詢到姓名 #{name}"
+
+  # 刪除操作
+  # 在雜湊表中刪除鍵值對 (key, val)
+  hashmap.remove(16750)
+  puts "\n刪除 16750 後，雜湊表為\nKey -> Value"
+  hashmap.print
+end