Merge branch 'krahets:master' into master

codes/c/chapter_computational_complexity/worst_best_time_complexity.c

@@ -15,12 +15,12 @@ int *randomNumbers(int n) {
         nums[i] = i + 1;
     }
     // 随机打乱数组元素 
-	for (int i = n - 1; i > 0; i--) {
-		int j = rand() % (i + 1);
-		int temp = nums[i];
-		nums[i] = nums[j];
-		nums[j] = temp; 
-	}
+    for (int i = n - 1; i > 0; i--) {
+        int j = rand() % (i + 1);
+        int temp = nums[i];
+        nums[i] = nums[j];
+        nums[j] = temp;
+    }
     return nums;
 }
 

codes/cpp/chapter_tree/avl_tree.cpp

@@ -1,228 +0,0 @@
-/**
- * File: avl_tree.cpp
- * Created Time: 2022-12-2
- * Author: mgisr (maguagua0706@gmail.com)
- */
-
-#include "../include/include.hpp"
-
-class AvlTree {
-private:
-    TreeNode *root{};
-    static bool isBalance(const TreeNode *p);
-    static int getBalanceFactor(const TreeNode *p);
-    static void updateHeight(TreeNode *p);
-    void fixBalance(TreeNode *p);
-    static bool isLeftChild(const TreeNode *p);
-    static TreeNode *&fromParentTo(TreeNode *node);
-public:
-    AvlTree() = default;
-    AvlTree(const AvlTree &p) = default;
-    const TreeNode *search(int val);
-    bool insert(int val);
-    bool remove(int val);
-    void printTree();
-};
-
-// 判断该结点是否平衡
-bool AvlTree::isBalance(const TreeNode *p) {
-    int balance_factor = getBalanceFactor(p);
-    if (-1 <= balance_factor && balance_factor <= 1) { return true; }
-    else { return false; }
-}
-
-// 获取当前结点的平衡因子
-int AvlTree::getBalanceFactor(const TreeNode *p) {
-    if (p->left == nullptr && p->right == nullptr) { return 0; }
-    else if (p->left == nullptr) { return (-1 - p->right->height); }
-    else if (p->right == nullptr) { return p->left->height + 1; }
-    else { return p->left->height - p->right->height; }
-}
-
-// 更新结点高度
-void AvlTree::updateHeight(TreeNode *p) {
-    if (p->left == nullptr && p->right == nullptr) { p->height = 0; }
-    else if (p->left == nullptr) { p->height = p->right->height + 1; }
-    else if (p->right == nullptr) { p->height = p->left->height + 1; }
-    else { p->height = std::max(p->left->height, p->right->height) + 1; }
-}
-
-void AvlTree::fixBalance(TreeNode *p) {
-    // 左旋操作
-    auto rotate_left = [&](TreeNode *node) -> TreeNode * {
-        TreeNode *temp = node->right;
-        temp->parent = p->parent;
-        node->right = temp->left;
-        if (temp->left != nullptr) {
-            temp->left->parent = node;
-        }
-        temp->left = node;
-        node->parent = temp;
-        updateHeight(node);
-        updateHeight(temp);
-        return temp;
-    };
-    // 右旋操作
-    auto rotate_right = [&](TreeNode *node) -> TreeNode * {
-        TreeNode *temp = node->left;
-        temp->parent = p->parent;
-        node->left = temp->right;
-        if (temp->right != nullptr) {
-            temp->right->parent = node;
-        }
-        temp->right = node;
-        node->parent = temp;
-        updateHeight(node);
-        updateHeight(temp);
-        return temp;
-    };
-    // 根据规则选取旋转方式
-    if (getBalanceFactor(p) > 1) {
-        if (getBalanceFactor(p->left) > 0) {
-            if (p->parent == nullptr) { root = rotate_right(p); }
-            else { fromParentTo(p) = rotate_right(p); }
-        } else {
-            p->left = rotate_left(p->left);
-            if (p->parent == nullptr) { root = rotate_right(p); }
-            else { fromParentTo(p) = rotate_right(p); }
-        }
-    } else {
-        if (getBalanceFactor(p->right) < 0) {
-            if (p->parent == nullptr) { root = rotate_left(p); }
-            else { fromParentTo(p) = rotate_left(p); }
-        } else {
-            p->right = rotate_right(p->right);
-            if (p->parent == nullptr) { root = rotate_left(p); }
-            else { fromParentTo(p) = rotate_left(p); }
-        }
-    }
-}
-
-// 判断当前结点是否为其父节点的左孩子
-bool AvlTree::isLeftChild(const TreeNode *p) {
-    if (p->parent == nullptr) { return false; }
-    return (p->parent->left == p);
-}
-
-// 返回父节点指向当前结点指针的引用
-TreeNode *&AvlTree::fromParentTo(TreeNode *node) {
-    if (isLeftChild(node)) { return node->parent->left; }
-    else { return node->parent->right; }
-}
-
-const TreeNode *AvlTree::search(int val) {
-    TreeNode *p = root;
-    while (p != nullptr) {
-        if (p->val == val) { return p; }
-        else if (p->val > val) { p = p->left; }
-        else { p = p->right; }
-    }
-    return nullptr;
-}
-
-bool AvlTree::insert(int val) {
-    TreeNode *p = root;
-    if (p == nullptr) {
-        root = new TreeNode(val);
-        return true;
-    }
-    for (;;) {
-        if (p->val == val) { return false; }
-        else if (p->val > val) {
-            if (p->left == nullptr) {
-                p->left = new TreeNode(val, p);
-                break;
-            } else {
-                p = p->left;
-            }
-        } else {
-            if (p->right == nullptr) {
-                p->right = new TreeNode(val, p);
-                break;
-            } else {
-                p = p->right;
-            }
-        }
-    }
-    for (; p != nullptr; p = p->parent) {
-        if (!isBalance(p)) {
-            fixBalance(p);
-            break;
-        } else { updateHeight(p); }
-    }
-    return true;
-}
-
-bool AvlTree::remove(int val) {
-    TreeNode *p = root;
-    if (p == nullptr) { return false; }
-    while (p != nullptr) {
-        if (p->val == val) {
-            TreeNode *real_delete_node = p;
-            TreeNode *next_node;
-            if (p->left == nullptr) {
-                next_node = p->right;
-                if (p->parent == nullptr) { root = next_node; }
-                else { fromParentTo(p) = next_node; }
-            } else if (p->right == nullptr) {
-                next_node = p->left;
-                if (p->parent == nullptr) { root = next_node; }
-                else { fromParentTo(p) = next_node; }
-            } else {
-                while (real_delete_node->left != nullptr) {
-                    real_delete_node = real_delete_node->left;
-                }
-                std::swap(p->val, real_delete_node->val);
-                next_node = real_delete_node->right;
-                if (real_delete_node->parent == p) { p->right = next_node; }
-                else { real_delete_node->parent->left = next_node; }
-            }
-            if (next_node != nullptr) {
-                next_node->parent = real_delete_node->parent;
-            }
-            for (p = real_delete_node; p != nullptr; p = p->parent) {
-                if (!isBalance(p)) { fixBalance(p); }
-                updateHeight(p);
-            }
-            delete real_delete_node;
-            return true;
-        } else if (p->val > val) {
-            p = p->left;
-        } else {
-            p = p->right;
-        }
-    }
-    return false;
-}
-
-void inOrder(const TreeNode *root) {
-    if (root == nullptr) return;
-    inOrder(root->left);
-    cout << root->val << ' ';
-    inOrder(root->right);
-}
-
-void AvlTree::printTree() {
-    inOrder(root);
-    cout << endl;
-}
-
-int main() {
-    AvlTree tree = AvlTree();
-    // tree.insert(13);
-    // tree.insert(24);
-    // tree.insert(37);
-    // tree.insert(90);
-    // tree.insert(53);
-
-    tree.insert(53);
-    tree.insert(90);
-    tree.insert(37);
-    tree.insert(24);
-    tree.insert(13);
-    tree.remove(90);
-    tree.printTree();
-    const TreeNode *p = tree.search(37);
-    cout << p->val;
-    return 0;
-}

codes/cpp/chapter_tree/binary_tree_bfs.cpp

@@ -30,8 +30,7 @@ vector<int> hierOrder(TreeNode* root) {
 int main() {
     /* 初始化二叉树 */
     // 这里借助了一个从数组直接生成二叉树的函数
-    TreeNode* root = vecToTree(vector<int> 
-        { 1, 2, 3, 4, 5, 6, 7, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX });
+    TreeNode* root = vecToTree(vector<int> { 1, 2, 3, 4, 5, 6, 7 });
     cout << endl << "初始化二叉树\n" << endl;
     PrintUtil::printTree(root);
 

codes/cpp/chapter_tree/binary_tree_dfs.cpp

@@ -41,8 +41,7 @@ void postOrder(TreeNode* root) {
 int main() {
     /* 初始化二叉树 */
     // 这里借助了一个从数组直接生成二叉树的函数
-    TreeNode* root = vecToTree(vector<int> 
-        { 1, 2, 3, 4, 5, 6, 7, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX});
+    TreeNode* root = vecToTree(vector<int> { 1, 2, 3, 4, 5, 6, 7 });
     cout << endl << "初始化二叉树\n" << endl;
     PrintUtil::printTree(root);
 

codes/cpp/include/PrintUtil.hpp

@@ -9,6 +9,7 @@
 #include <iostream>
 #include <string>
 #include <sstream>
+#include <climits>
 #include "ListNode.hpp"
 #include "TreeNode.hpp"
 

codes/cpp/include/TreeNode.hpp

@@ -27,23 +27,24 @@ struct TreeNode {
  * @return TreeNode* 
  */
 TreeNode *vecToTree(vector<int> list) {
-    if (list.empty()) {
+    if (list.empty())
         return nullptr;
-    }
 
     auto *root = new TreeNode(list[0]);
     queue<TreeNode *> que;
-    size_t n = list.size(), index = 1;
-    while (index < n) {
+    que.emplace(root);
+    size_t n = list.size(), index = 0;
+    while (!que.empty()) {
         auto node = que.front();
         que.pop();
-
+        if (++index >= n) break;
         if (index < n) {
-            node->left = new TreeNode(list[index++]);
+            node->left = new TreeNode(list[index]);
             que.emplace(node->left);
         }
+        if (++index >= n) break;
         if (index < n) {
-            node->right = new TreeNode(list[index++]);
+            node->right = new TreeNode(list[index]);
             que.emplace(node->right);
         }
     }

codes/csharp/chapter_tree/binary_tree_bfs.cs

@@ -41,8 +41,7 @@ namespace hello_algo.chapter_tree
         {
             /* 初始化二叉树 */
             // 这里借助了一个从数组直接生成二叉树的函数
-            TreeNode? root = TreeNode.ArrToTree(new int?[] { 
-                1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null});
+            TreeNode? root = TreeNode.ArrToTree(new int?[] { 1, 2, 3, 4, 5, 6, 7 });
             Console.WriteLine("\n初始化二叉树\n");
             PrintUtil.PrintTree(root);
 

codes/csharp/chapter_tree/binary_tree_dfs.cs

@@ -57,8 +57,7 @@ namespace hello_algo.chapter_tree
         {
             /* 初始化二叉树 */
             // 这里借助了一个从数组直接生成二叉树的函数
-            TreeNode? root = TreeNode.ArrToTree(new int?[] { 
-                1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null});
+            TreeNode? root = TreeNode.ArrToTree(new int?[] { 1, 2, 3, 4, 5, 6, 7 });
             Console.WriteLine("\n初始化二叉树\n");
             PrintUtil.PrintTree(root);
 

codes/csharp/hello-algo.csproj

@@ -11,8 +11,8 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />
     <PackageReference Include="NUnit" Version="3.13.3" />
-	<PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
-	<PackageReference Include="coverlet.collector" Version="3.1.0" />
+  <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+  <PackageReference Include="coverlet.collector" Version="3.1.0" />
   </ItemGroup>
 
 </Project>

codes/csharp/include/TreeNode.cs

@@ -19,7 +19,7 @@ namespace hello_algo.include
         }
 
         /**
-         * Generate a binary tree with an array
+         * Generate a binary tree given an array
          * @param arr
          * @return
          */
@@ -31,22 +31,22 @@ namespace hello_algo.include
             TreeNode root = new TreeNode((int) arr[0]);
             Queue<TreeNode> queue = new Queue<TreeNode>();
             queue.Enqueue(root);
-            int i = 1;
-            while (queue.Count!=0)
+            int i = 0;
+            while (queue.Count != 0)
             {
                 TreeNode node = queue.Dequeue();
+                if (++i >= arr.Length) break;
                 if (arr[i] != null)
                 {
                     node.left = new TreeNode((int) arr[i]);
                     queue.Enqueue(node.left);
                 }
-                i++;
+                if (++i >= arr.Length) break;
                 if (arr[i] != null)
                 {
                     node.right = new TreeNode((int) arr[i]);
                     queue.Enqueue(node.right);
                 }
-                i++;
             }
             return root;
         }

codes/go/chapter_array_and_linkedlist/my_list.go

@@ -5,7 +5,7 @@
 package chapter_array_and_linkedlist
 
 /* 列表类简易实现 */
-type MyList struct {
+type myList struct {
 	numsCapacity int
 	nums         []int
 	numsSize     int
@@ -13,8 +13,8 @@ type MyList struct {
 }
 
 /* 构造函数 */
-func newMyList() *MyList {
-	return &MyList{
+func newMyList() *myList {
+	return &myList{
 		numsCapacity: 10,              // 列表容量
 		nums:         make([]int, 10), // 数组（存储列表元素）
 		numsSize:     0,               // 列表长度（即当前元素数量）
@@ -23,17 +23,17 @@ func newMyList() *MyList {
 }
 
 /* 获取列表长度（即当前元素数量） */
-func (l *MyList) size() int {
+func (l *myList) size() int {
 	return l.numsSize
 }
 
 /*  获取列表容量 */
-func (l *MyList) capacity() int {
+func (l *myList) capacity() int {
 	return l.numsCapacity
 }
 
 /* 访问元素 */
-func (l *MyList) get(index int) int {
+func (l *myList) get(index int) int {
 	// 索引如果越界则抛出异常，下同
 	if index >= l.numsSize {
 		panic("索引越界")
@@ -42,7 +42,7 @@ func (l *MyList) get(index int) int {
 }
 
 /* 更新元素 */
-func (l *MyList) set(num, index int) {
+func (l *myList) set(num, index int) {
 	if index >= l.numsSize {
 		panic("索引越界")
 	}
@@ -50,7 +50,7 @@ func (l *MyList) set(num, index int) {
 }
 
 /* 尾部添加元素 */
-func (l *MyList) add(num int) {
+func (l *myList) add(num int) {
 	// 元素数量超出容量时，触发扩容机制
 	if l.numsSize == l.numsCapacity {
 		l.extendCapacity()
@@ -61,7 +61,7 @@ func (l *MyList) add(num int) {
 }
 
 /* 中间插入元素 */
-func (l *MyList) insert(num, index int) {
+func (l *myList) insert(num, index int) {
 	if index >= l.numsSize {
 		panic("索引越界")
 	}
@@ -79,7 +79,7 @@ func (l *MyList) insert(num, index int) {
 }
 
 /* 删除元素 */
-func (l *MyList) remove(index int) int {
+func (l *myList) remove(index int) int {
 	if index >= l.numsSize {
 		panic("索引越界")
 	}
@@ -95,7 +95,7 @@ func (l *MyList) remove(index int) int {
 }
 
 /* 列表扩容 */
-func (l *MyList) extendCapacity() {
+func (l *myList) extendCapacity() {
 	// 新建一个长度为 self.__size 的数组，并将原数组拷贝到新数组
 	l.nums = append(l.nums, make([]int, l.numsCapacity*(l.extendRatio-1))...)
 	// 更新列表容量
@@ -103,7 +103,7 @@ func (l *MyList) extendCapacity() {
 }
 
 /* 返回有效长度的列表 */
-func (l *MyList) toArray() []int {
+func (l *myList) toArray() []int {
 	// 仅转换有效长度范围内的列表元素
 	return l.nums[:l.numsSize]
 }

codes/go/chapter_computational_complexity/space_complexity.go

@@ -9,31 +9,31 @@ import (
 	"strconv"
 )
 
-/* Node 结构体 */
-type Node struct {
+/* 结构体 */
+type node struct {
 	val  int
-	next *Node
+	next *node
 }
 
-/* TreeNode 二叉树 */
-type TreeNode struct {
+/* treeNode 二叉树 */
+type treeNode struct {
 	val   int
-	left  *TreeNode
-	right *TreeNode
+	left  *treeNode
+	right *treeNode
 }
 
-/* 创建 Node 结构体  */
-func newNode(val int) *Node {
-	return &Node{val: val}
+/* 创建 node 结构体  */
+func newNode(val int) *node {
+	return &node{val: val}
 }
 
-/* 创建 TreeNode 结构体 */
-func newTreeNode(val int) *TreeNode {
-	return &TreeNode{val: val}
+/* 创建 treeNode 结构体 */
+func newTreeNode(val int) *treeNode {
+	return &treeNode{val: val}
 }
 
 /* 输出二叉树 */
-func printTree(root *TreeNode) {
+func printTree(root *treeNode) {
 	if root == nil {
 		return
 	}
@@ -72,7 +72,7 @@ func spaceLinear(n int) {
 	// 长度为 n 的数组占用 O(n) 空间
 	_ = make([]int, n)
 	// 长度为 n 的列表占用 O(n) 空间
-	var nodes []*Node
+	var nodes []*node
 	for i := 0; i < n; i++ {
 		nodes = append(nodes, newNode(i))
 	}
@@ -112,7 +112,7 @@ func spaceQuadraticRecur(n int) int {
 }
 
 /* 指数阶（建立满二叉树） */
-func buildTree(n int) *TreeNode {
+func buildTree(n int) *treeNode {
 	if n == 0 {
 		return nil
 	}

codes/go/chapter_hashing/array_hash_map.go

@@ -7,30 +7,30 @@ package chapter_hashing
 import "fmt"
 
 /* 键值对 int->String */
-type Entry struct {
+type entry struct {
 	key int
 	val string
 }
 
 /* 基于数组简易实现的哈希表 */
-type ArrayHashMap struct {
-	bucket []*Entry
+type arrayHashMap struct {
+	bucket []*entry
 }
 
-func newArrayHashMap() *ArrayHashMap {
+func newArrayHashMap() *arrayHashMap {
 	// 初始化一个长度为 100 的桶（数组）
-	bucket := make([]*Entry, 100)
-	return &ArrayHashMap{bucket: bucket}
+	bucket := make([]*entry, 100)
+	return &arrayHashMap{bucket: bucket}
 }
 
 /* 哈希函数 */
-func (a *ArrayHashMap) hashFunc(key int) int {
+func (a *arrayHashMap) hashFunc(key int) int {
 	index := key % 100
 	return index
 }
 
 /* 查询操作 */
-func (a *ArrayHashMap) get(key int) string {
+func (a *arrayHashMap) get(key int) string {
 	index := a.hashFunc(key)
 	pair := a.bucket[index]
 	if pair == nil {
@@ -40,22 +40,22 @@ func (a *ArrayHashMap) get(key int) string {
 }
 
 /* 添加操作 */
-func (a *ArrayHashMap) put(key int, val string) {
-	pair := &Entry{key: key, val: val}
+func (a *arrayHashMap) put(key int, val string) {
+	pair := &entry{key: key, val: val}
 	index := a.hashFunc(key)
 	a.bucket[index] = pair
 }
 
 /* 删除操作 */
-func (a *ArrayHashMap) remove(key int) {
+func (a *arrayHashMap) remove(key int) {
 	index := a.hashFunc(key)
 	// 置为 nil ，代表删除
 	a.bucket[index] = nil
 }
 
 /* 获取所有键对 */
-func (a *ArrayHashMap) entrySet() []*Entry {
-	var pairs []*Entry
+func (a *arrayHashMap) entrySet() []*entry {
+	var pairs []*entry
 	for _, pair := range a.bucket {
 		if pair != nil {
 			pairs = append(pairs, pair)
@@ -65,7 +65,7 @@ func (a *ArrayHashMap) entrySet() []*Entry {
 }
 
 /* 获取所有键 */
-func (a *ArrayHashMap) keySet() []int {
+func (a *arrayHashMap) keySet() []int {
 	var keys []int
 	for _, pair := range a.bucket {
 		if pair != nil {
@@ -76,7 +76,7 @@ func (a *ArrayHashMap) keySet() []int {
 }
 
 /* 获取所有值 */
-func (a *ArrayHashMap) valueSet() []string {
+func (a *arrayHashMap) valueSet() []string {
 	var values []string
 	for _, pair := range a.bucket {
 		if pair != nil {
@@ -87,7 +87,7 @@ func (a *ArrayHashMap) valueSet() []string {
 }
 
 /* 打印哈希表 */
-func (a *ArrayHashMap) print() {
+func (a *arrayHashMap) print() {
 	for _, pair := range a.bucket {
 		if pair != nil {
 			fmt.Println(pair.key, "->", pair.val)

codes/go/chapter_searching/hashing_search_test.go

@@ -6,8 +6,9 @@ package chapter_searching
 
 import (
 	"fmt"
-	. "github.com/krahets/hello-algo/pkg"
 	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
 )
 
 func TestHashingSearch(t *testing.T) {

codes/go/chapter_sorting/merge_sort.go

@@ -8,25 +8,25 @@ package chapter_sorting
 // 左子数组区间 [left, mid]
 // 右子数组区间 [mid + 1, right]
 func merge(nums []int, left, mid, right int) {
-	// 初始化辅助数组 借助 copy模块
+	// 初始化辅助数组 借助 copy 模块
 	tmp := make([]int, right-left+1)
 	for i := left; i <= right; i++ {
 		tmp[i-left] = nums[i]
 	}
 	// 左子数组的起始索引和结束索引
-	left_start, left_end := left-left, mid-left
+	leftStart, leftEnd := left-left, mid-left
 	// 右子数组的起始索引和结束索引
-	right_start, right_end := mid+1-left, right-left
+	rightStart, rightEnd := mid+1-left, right-left
 	// i, j 分别指向左子数组、右子数组的首元素
-	i, j := left_start, right_start
+	i, j := leftStart, rightStart
 	// 通过覆盖原数组 nums 来合并左子数组和右子数组
 	for k := left; k <= right; k++ {
 		// 若“左子数组已全部合并完”，则选取右子数组元素，并且 j++
-		if i > left_end {
+		if i > leftEnd {
 			nums[k] = tmp[j]
 			j++
 			// 否则，若“右子数组已全部合并完”或“左子数组元素 <= 右子数组元素”，则选取左子数组元素，并且 i++
-		} else if j > right_end || tmp[i] <= tmp[j] {
+		} else if j > rightEnd || tmp[i] <= tmp[j] {
 			nums[k] = tmp[i]
 			i++
 			// 否则，若“左右子数组都未全部合并完”且“左子数组元素 > 右子数组元素”，则选取右子数组元素，并且 j++

codes/go/chapter_sorting/quick_sort.go

@@ -5,16 +5,16 @@
 package chapter_sorting
 
 // 快速排序
-type QuickSort struct{}
+type quickSort struct{}
 
 // 快速排序（中位基准数优化）
-type QuickSortMedian struct{}
+type quickSortMedian struct{}
 
 // 快速排序（尾递归优化）
-type QuickSortTailCall struct{}
+type quickSortTailCall struct{}
 
 /* 哨兵划分 */
-func (q *QuickSort) partition(nums []int, left, right int) int {
+func (q *quickSort) partition(nums []int, left, right int) int {
 	// 以 nums[left] 作为基准数
 	i, j := left, right
 	for i < j {
@@ -33,7 +33,7 @@ func (q *QuickSort) partition(nums []int, left, right int) int {
 }
 
 /* 快速排序 */
-func (q *QuickSort) quickSort(nums []int, left, right int) {
+func (q *quickSort) quickSort(nums []int, left, right int) {
 	// 子数组长度为 1 时终止递归
 	if left >= right {
 		return
@@ -46,7 +46,7 @@ func (q *QuickSort) quickSort(nums []int, left, right int) {
 }
 
 /* 选取三个元素的中位数 */
-func (q *QuickSortMedian) medianThree(nums []int, left, mid, right int) int {
+func (q *quickSortMedian) medianThree(nums []int, left, mid, right int) int {
 	if (nums[left] > nums[mid]) != (nums[left] > nums[right]) {
 		return left
 	} else if (nums[mid] < nums[left]) != (nums[mid] > nums[right]) {
@@ -56,7 +56,7 @@ func (q *QuickSortMedian) medianThree(nums []int, left, mid, right int) int {
 }
 
 /* 哨兵划分（三数取中值）*/
-func (q *QuickSortMedian) partition(nums []int, left, right int) int {
+func (q *quickSortMedian) partition(nums []int, left, right int) int {
 	// 以 nums[left] 作为基准数
 	med := q.medianThree(nums, left, (left+right)/2, right)
 	// 将中位数交换至数组最左端
@@ -79,7 +79,7 @@ func (q *QuickSortMedian) partition(nums []int, left, right int) int {
 }
 
 /* 快速排序 */
-func (q *QuickSortMedian) quickSort(nums []int, left, right int) {
+func (q *quickSortMedian) quickSort(nums []int, left, right int) {
 	// 子数组长度为 1 时终止递归
 	if left >= right {
 		return
@@ -92,7 +92,7 @@ func (q *QuickSortMedian) quickSort(nums []int, left, right int) {
 }
 
 /* 哨兵划分 */
-func (q *QuickSortTailCall) partition(nums []int, left, right int) int {
+func (q *quickSortTailCall) partition(nums []int, left, right int) int {
 	// 以 nums[left] 作为基准数
 	i, j := left, right
 	for i < j {
@@ -111,7 +111,7 @@ func (q *QuickSortTailCall) partition(nums []int, left, right int) int {
 }
 
 /* 快速排序（尾递归优化）*/
-func (q *QuickSortTailCall) quickSort(nums []int, left, right int) {
+func (q *quickSortTailCall) quickSort(nums []int, left, right int) {
 	// 子数组长度为 1 时终止
 	for left < right {
 		// 哨兵划分操作

codes/go/chapter_sorting/quick_sort_test.go

@@ -11,7 +11,7 @@ import (
 
 // 快速排序
 func TestQuickSort(t *testing.T) {
-	q := QuickSort{}
+	q := quickSort{}
 	nums := []int{4, 1, 3, 1, 5, 2}
 	q.quickSort(nums, 0, len(nums)-1)
 	fmt.Println("快速排序完成后 nums = ", nums)
@@ -19,7 +19,7 @@ func TestQuickSort(t *testing.T) {
 
 // 快速排序（中位基准数优化）
 func TestQuickSortMedian(t *testing.T) {
-	q := QuickSortMedian{}
+	q := quickSortMedian{}
 	nums := []int{4, 1, 3, 1, 5, 2}
 	q.quickSort(nums, 0, len(nums)-1)
 	fmt.Println("快速排序（中位基准数优化）完成后 nums = ", nums)
@@ -27,7 +27,7 @@ func TestQuickSortMedian(t *testing.T) {
 
 // 快速排序（尾递归优化）
 func TestQuickSortTailCall(t *testing.T) {
-	q := QuickSortTailCall{}
+	q := quickSortTailCall{}
 	nums := []int{4, 1, 3, 1, 5, 2}
 	q.quickSort(nums, 0, len(nums)-1)
 	fmt.Println("快速排序（尾递归优化）完成后 nums = ", nums)

codes/go/chapter_stack_and_queue/array_queue.go

@@ -5,16 +5,16 @@
 package chapter_stack_and_queue
 
 /* 基于环形数组实现的队列 */
-type ArrayQueue struct {
+type arrayQueue struct {
 	data     []int // 用于存储队列元素的数组
 	capacity int   // 队列容量（即最多容量的元素个数）
 	front    int   // 头指针，指向队首
 	rear     int   // 尾指针，指向队尾 + 1
 }
 
-// NewArrayQueue 基于环形数组实现的队列
-func NewArrayQueue(capacity int) *ArrayQueue {
-	return &ArrayQueue{
+// newArrayQueue 基于环形数组实现的队列
+func newArrayQueue(capacity int) *arrayQueue {
+	return &arrayQueue{
 		data:     make([]int, capacity),
 		capacity: capacity,
 		front:    0,
@@ -22,21 +22,21 @@ func NewArrayQueue(capacity int) *ArrayQueue {
 	}
 }
 
-// Size 获取队列的长度
-func (q *ArrayQueue) Size() int {
+// size 获取队列的长度
+func (q *arrayQueue) size() int {
 	size := (q.capacity + q.rear - q.front) % q.capacity
 	return size
 }
 
-// IsEmpty 判断队列是否为空
-func (q *ArrayQueue) IsEmpty() bool {
+// isEmpty 判断队列是否为空
+func (q *arrayQueue) isEmpty() bool {
 	return q.rear-q.front == 0
 }
 
-// Offer 入队
-func (q *ArrayQueue) Offer(v int) {
+// offer 入队
+func (q *arrayQueue) offer(v int) {
 	// 当 rear == capacity 表示队列已满
-	if q.Size() == q.capacity {
+	if q.size() == q.capacity {
 		return
 	}
 	// 尾结点后添加
@@ -45,9 +45,9 @@ func (q *ArrayQueue) Offer(v int) {
 	q.rear = (q.rear + 1) % q.capacity
 }
 
-// Poll 出队
-func (q *ArrayQueue) Poll() any {
-	if q.IsEmpty() {
+// poll 出队
+func (q *arrayQueue) poll() any {
+	if q.isEmpty() {
 		return nil
 	}
 	v := q.data[q.front]
@@ -56,9 +56,9 @@ func (q *ArrayQueue) Poll() any {
 	return v
 }
 
-// Peek 访问队首元素
-func (q *ArrayQueue) Peek() any {
-	if q.IsEmpty() {
+// peek 访问队首元素
+func (q *arrayQueue) peek() any {
+	if q.isEmpty() {
 		return nil
 	}
 	v := q.data[q.front]
@@ -66,6 +66,6 @@ func (q *ArrayQueue) Peek() any {
 }
 
 // 获取 Slice 用于打印
-func (s *ArrayQueue) toSlice() []int {
-	return s.data[s.front:s.rear]
+func (q *arrayQueue) toSlice() []int {
+	return q.data[q.front:q.rear]
 }

codes/go/chapter_stack_and_queue/array_stack.go

@@ -5,47 +5,47 @@
 package chapter_stack_and_queue
 
 /* 基于数组实现的栈 */
-type ArrayStack struct {
+type arrayStack struct {
 	data []int // 数据
 }
 
-func NewArrayStack() *ArrayStack {
-	return &ArrayStack{
+func newArrayStack() *arrayStack {
+	return &arrayStack{
 		// 设置栈的长度为 0，容量为 16
 		data: make([]int, 0, 16),
 	}
 }
 
-// Size 栈的长度
-func (s *ArrayStack) Size() int {
+// size 栈的长度
+func (s *arrayStack) size() int {
 	return len(s.data)
 }
 
-// IsEmpty 栈是否为空
-func (s *ArrayStack) IsEmpty() bool {
-	return s.Size() == 0
+// isEmpty 栈是否为空
+func (s *arrayStack) isEmpty() bool {
+	return s.size() == 0
 }
 
-// Push 入栈
-func (s *ArrayStack) Push(v int) {
+// push 入栈
+func (s *arrayStack) push(v int) {
 	// 切片会自动扩容
 	s.data = append(s.data, v)
 }
 
-// Pop 出栈
-func (s *ArrayStack) Pop() any {
+// pop 出栈
+func (s *arrayStack) pop() any {
 	// 弹出栈前，先判断是否为空
-	if s.IsEmpty() {
+	if s.isEmpty() {
 		return nil
 	}
-	val := s.Peek()
+	val := s.peek()
 	s.data = s.data[:len(s.data)-1]
 	return val
 }
 
-// Peek 获取栈顶元素
-func (s *ArrayStack) Peek() any {
-	if s.IsEmpty() {
+// peek 获取栈顶元素
+func (s *arrayStack) peek() any {
+	if s.isEmpty() {
 		return nil
 	}
 	val := s.data[len(s.data)-1]
@@ -53,6 +53,6 @@ func (s *ArrayStack) Peek() any {
 }
 
 // 获取 Slice 用于打印
-func (s *ArrayStack) toSlice() []int {
+func (s *arrayStack) toSlice() []int {
 	return s.data
 }

codes/go/chapter_stack_and_queue/deque_test.go

@@ -51,48 +51,48 @@ func TestDeque(t *testing.T) {
 
 func TestLinkedListDeque(t *testing.T) {
 	// 初始化队列
-	deque := NewLinkedListDeque()
+	deque := newLinkedListDeque()
 
 	// 元素入队
-	deque.OfferLast(2)
-	deque.OfferLast(5)
-	deque.OfferLast(4)
-	deque.OfferFirst(3)
-	deque.OfferFirst(1)
+	deque.offerLast(2)
+	deque.offerLast(5)
+	deque.offerLast(4)
+	deque.offerFirst(3)
+	deque.offerFirst(1)
 	fmt.Print("队列 deque = ")
 	PrintList(deque.toList())
 
 	// 访问队首元素
-	front := deque.PeekFirst()
+	front := deque.peekFirst()
 	fmt.Println("队首元素 front =", front)
-	rear := deque.PeekLast()
+	rear := deque.peekLast()
 	fmt.Println("队尾元素 rear =", rear)
 
 	// 元素出队
-	pollFirst := deque.PollFirst()
+	pollFirst := deque.pollFirst()
 	fmt.Print("队首出队元素 pollFirst = ", pollFirst, "，队首出队后 deque = ")
 	PrintList(deque.toList())
-	pollLast := deque.PollLast()
+	pollLast := deque.pollLast()
 	fmt.Print("队尾出队元素 pollLast = ", pollLast, "，队尾出队后 deque = ")
 	PrintList(deque.toList())
 
 	// 获取队的长度
-	size := deque.Size()
+	size := deque.size()
 	fmt.Println("队的长度 size =", size)
 
 	// 判断是否为空
-	isEmpty := deque.IsEmpty()
+	isEmpty := deque.isEmpty()
 	fmt.Println("队是否为空 =", isEmpty)
 }
 
 // BenchmarkArrayQueue 67.92 ns/op in Mac M1 Pro
 func BenchmarkLinkedListDeque(b *testing.B) {
-	stack := NewLinkedListDeque()
+	stack := newLinkedListDeque()
 	// use b.N for looping
 	for i := 0; i < b.N; i++ {
-		stack.OfferLast(777)
+		stack.offerLast(777)
 	}
 	for i := 0; i < b.N; i++ {
-		stack.PollFirst()
+		stack.pollFirst()
 	}
 }

codes/go/chapter_stack_and_queue/linkedlist_deque.go

@@ -8,31 +8,31 @@ import (
 	"container/list"
 )
 
-// LinkedListDeque 基于链表实现的双端队列, 使用内置包 list 来实现栈
-type LinkedListDeque struct {
+// linkedListDeque 基于链表实现的双端队列, 使用内置包 list 来实现栈
+type linkedListDeque struct {
 	data *list.List
 }
 
-// NewLinkedListDeque 初始化双端队列
-func NewLinkedListDeque() *LinkedListDeque {
-	return &LinkedListDeque{
+// newLinkedListDeque 初始化双端队列
+func newLinkedListDeque() *linkedListDeque {
+	return &linkedListDeque{
 		data: list.New(),
 	}
 }
 
-// OfferFirst 队首元素入队
-func (s *LinkedListDeque) OfferFirst(value any) {
+// offerFirst 队首元素入队
+func (s *linkedListDeque) offerFirst(value any) {
 	s.data.PushFront(value)
 }
 
-// OfferLast 队尾元素入队
-func (s *LinkedListDeque) OfferLast(value any) {
+// offerLast 队尾元素入队
+func (s *linkedListDeque) offerLast(value any) {
 	s.data.PushBack(value)
 }
 
-// PollFirst 队首元素出队
-func (s *LinkedListDeque) PollFirst() any {
-	if s.IsEmpty() {
+// pollFirst 队首元素出队
+func (s *linkedListDeque) pollFirst() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Front()
@@ -40,9 +40,9 @@ func (s *LinkedListDeque) PollFirst() any {
 	return e.Value
 }
 
-// PollLast 队尾元素出队
-func (s *LinkedListDeque) PollLast() any {
-	if s.IsEmpty() {
+// pollLast 队尾元素出队
+func (s *linkedListDeque) pollLast() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Back()
@@ -50,35 +50,35 @@ func (s *LinkedListDeque) PollLast() any {
 	return e.Value
 }
 
-// PeekFirst 访问队首元素
-func (s *LinkedListDeque) PeekFirst() any {
-	if s.IsEmpty() {
+// peekFirst 访问队首元素
+func (s *linkedListDeque) peekFirst() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Front()
 	return e.Value
 }
 
-// PeekLast 访问队尾元素
-func (s *LinkedListDeque) PeekLast() any {
-	if s.IsEmpty() {
+// peekLast 访问队尾元素
+func (s *linkedListDeque) peekLast() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Back()
 	return e.Value
 }
 
-// Size 获取队列的长度
-func (s *LinkedListDeque) Size() int {
+// size 获取队列的长度
+func (s *linkedListDeque) size() int {
 	return s.data.Len()
 }
 
-// IsEmpty 判断队列是否为空
-func (s *LinkedListDeque) IsEmpty() bool {
+// isEmpty 判断队列是否为空
+func (s *linkedListDeque) isEmpty() bool {
 	return s.data.Len() == 0
 }
 
 // 获取 List 用于打印
-func (s *LinkedListDeque) toList() *list.List {
+func (s *linkedListDeque) toList() *list.List {
 	return s.data
 }

codes/go/chapter_stack_and_queue/linkedlist_queue.go

@@ -9,26 +9,26 @@ import (
 )
 
 /* 基于链表实现的队列 */
-type LinkedListQueue struct {
+type linkedListQueue struct {
 	// 使用内置包 list 来实现队列
 	data *list.List
 }
 
-// NewLinkedListQueue 初始化链表
-func NewLinkedListQueue() *LinkedListQueue {
-	return &LinkedListQueue{
+// newLinkedListQueue 初始化链表
+func newLinkedListQueue() *linkedListQueue {
+	return &linkedListQueue{
 		data: list.New(),
 	}
 }
 
-// Offer 入队
-func (s *LinkedListQueue) Offer(value any) {
+// offer 入队
+func (s *linkedListQueue) offer(value any) {
 	s.data.PushBack(value)
 }
 
-// Poll 出队
-func (s *LinkedListQueue) Poll() any {
-	if s.IsEmpty() {
+// poll 出队
+func (s *linkedListQueue) poll() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Front()
@@ -36,26 +36,26 @@ func (s *LinkedListQueue) Poll() any {
 	return e.Value
 }
 
-// Peek 访问队首元素
-func (s *LinkedListQueue) Peek() any {
-	if s.IsEmpty() {
+// peek 访问队首元素
+func (s *linkedListQueue) peek() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Front()
 	return e.Value
 }
 
-// Size 获取队列的长度
-func (s *LinkedListQueue) Size() int {
+// size 获取队列的长度
+func (s *linkedListQueue) size() int {
 	return s.data.Len()
 }
 
-// IsEmpty 判断队列是否为空
-func (s *LinkedListQueue) IsEmpty() bool {
+// isEmpty 判断队列是否为空
+func (s *linkedListQueue) isEmpty() bool {
 	return s.data.Len() == 0
 }
 
 // 获取 List 用于打印
-func (s *LinkedListQueue) toList() *list.List {
+func (s *linkedListQueue) toList() *list.List {
 	return s.data
 }

codes/go/chapter_stack_and_queue/linkedlist_stack.go

@@ -9,26 +9,26 @@ import (
 )
 
 /* 基于链表实现的栈 */
-type LinkedListStack struct {
+type linkedListStack struct {
 	// 使用内置包 list 来实现栈
 	data *list.List
 }
 
-// NewLinkedListStack 初始化链表
-func NewLinkedListStack() *LinkedListStack {
-	return &LinkedListStack{
+// newLinkedListStack 初始化链表
+func newLinkedListStack() *linkedListStack {
+	return &linkedListStack{
 		data: list.New(),
 	}
 }
 
-// Push 入栈
-func (s *LinkedListStack) Push(value int) {
+// push 入栈
+func (s *linkedListStack) push(value int) {
 	s.data.PushBack(value)
 }
 
-// Pop 出栈
-func (s *LinkedListStack) Pop() any {
-	if s.IsEmpty() {
+// pop 出栈
+func (s *linkedListStack) pop() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Back()
@@ -36,26 +36,26 @@ func (s *LinkedListStack) Pop() any {
 	return e.Value
 }
 
-// Peek 访问栈顶元素
-func (s *LinkedListStack) Peek() any {
-	if s.IsEmpty() {
+// peek 访问栈顶元素
+func (s *linkedListStack) peek() any {
+	if s.isEmpty() {
 		return nil
 	}
 	e := s.data.Back()
 	return e.Value
 }
 
-// Size 获取栈的长度
-func (s *LinkedListStack) Size() int {
+// size 获取栈的长度
+func (s *linkedListStack) size() int {
 	return s.data.Len()
 }
 
-// IsEmpty 判断栈是否为空
-func (s *LinkedListStack) IsEmpty() bool {
+// isEmpty 判断栈是否为空
+func (s *linkedListStack) isEmpty() bool {
 	return s.data.Len() == 0
 }
 
 // 获取 List 用于打印
-func (s *LinkedListStack) toList() *list.List {
+func (s *linkedListStack) toList() *list.List {
 	return s.data
 }

codes/go/chapter_stack_and_queue/queue_test.go

@@ -48,87 +48,87 @@ func TestQueue(t *testing.T) {
 func TestArrayQueue(t *testing.T) {
 	// 初始化队列，使用队列的通用接口
 	capacity := 10
-	queue := NewArrayQueue(capacity)
+	queue := newArrayQueue(capacity)
 
 	// 元素入队
-	queue.Offer(1)
-	queue.Offer(3)
-	queue.Offer(2)
-	queue.Offer(5)
-	queue.Offer(4)
+	queue.offer(1)
+	queue.offer(3)
+	queue.offer(2)
+	queue.offer(5)
+	queue.offer(4)
 	fmt.Print("队列 queue = ")
 	PrintSlice(queue.toSlice())
 
 	// 访问队首元素
-	peek := queue.Peek()
+	peek := queue.peek()
 	fmt.Println("队首元素 peek =", peek)
 
 	// 元素出队
-	poll := queue.Poll()
+	poll := queue.poll()
 	fmt.Print("出队元素 poll = ", poll, ", 出队后 queue = ")
 	PrintSlice(queue.toSlice())
 
 	// 获取队的长度
-	size := queue.Size()
+	size := queue.size()
 	fmt.Println("队的长度 size =", size)
 
 	// 判断是否为空
-	isEmpty := queue.IsEmpty()
+	isEmpty := queue.isEmpty()
 	fmt.Println("队是否为空 =", isEmpty)
 }
 
 func TestLinkedListQueue(t *testing.T) {
 	// 初始化队
-	queue := NewLinkedListQueue()
+	queue := newLinkedListQueue()
 
 	// 元素入队
-	queue.Offer(1)
-	queue.Offer(3)
-	queue.Offer(2)
-	queue.Offer(5)
-	queue.Offer(4)
+	queue.offer(1)
+	queue.offer(3)
+	queue.offer(2)
+	queue.offer(5)
+	queue.offer(4)
 	fmt.Print("队列 queue = ")
 	PrintList(queue.toList())
 
 	// 访问队首元素
-	peek := queue.Peek()
+	peek := queue.peek()
 	fmt.Println("队首元素 peek =", peek)
 
 	// 元素出队
-	poll := queue.Poll()
+	poll := queue.poll()
 	fmt.Print("出队元素 poll = ", poll, ", 出队后 queue = ")
 	PrintList(queue.toList())
 
 	// 获取队的长度
-	size := queue.Size()
+	size := queue.size()
 	fmt.Println("队的长度 size =", size)
 
 	// 判断是否为空
-	isEmpty := queue.IsEmpty()
+	isEmpty := queue.isEmpty()
 	fmt.Println("队是否为空 =", isEmpty)
 }
 
 // BenchmarkArrayQueue 8 ns/op in Mac M1 Pro
 func BenchmarkArrayQueue(b *testing.B) {
 	capacity := 1000
-	stack := NewArrayQueue(capacity)
+	stack := newArrayQueue(capacity)
 	// use b.N for looping
 	for i := 0; i < b.N; i++ {
-		stack.Offer(777)
+		stack.offer(777)
 	}
 	for i := 0; i < b.N; i++ {
-		stack.Poll()
+		stack.poll()
 	}
 }
 
 // BenchmarkLinkedQueue 62.66 ns/op in Mac M1 Pro
 func BenchmarkLinkedQueue(b *testing.B) {
-	stack := NewLinkedListQueue()
+	stack := newLinkedListQueue()
 	// use b.N for looping
 	for i := 0; i < b.N; i++ {
-		stack.Offer(777)
+		stack.offer(777)
 	}
 	for i := 0; i < b.N; i++ {
-		stack.Poll()
+		stack.poll()
 	}
 }

codes/go/chapter_stack_and_queue/stack_test.go

@@ -46,85 +46,85 @@ func TestStack(t *testing.T) {
 
 func TestArrayStack(t *testing.T) {
 	// 初始化栈, 使用接口承接
-	stack := NewArrayStack()
+	stack := newArrayStack()
 
 	// 元素入栈
-	stack.Push(1)
-	stack.Push(3)
-	stack.Push(2)
-	stack.Push(5)
-	stack.Push(4)
+	stack.push(1)
+	stack.push(3)
+	stack.push(2)
+	stack.push(5)
+	stack.push(4)
 	fmt.Print("栈 stack = ")
 	PrintSlice(stack.toSlice())
 
 	// 访问栈顶元素
-	peek := stack.Peek()
+	peek := stack.peek()
 	fmt.Println("栈顶元素 peek =", peek)
 
 	// 元素出栈
-	pop := stack.Pop()
+	pop := stack.pop()
 	fmt.Print("出栈元素 pop = ", pop, ", 出栈后 stack = ")
 	PrintSlice(stack.toSlice())
 
 	// 获取栈的长度
-	size := stack.Size()
+	size := stack.size()
 	fmt.Println("栈的长度 size =", size)
 
 	// 判断是否为空
-	isEmpty := stack.IsEmpty()
+	isEmpty := stack.isEmpty()
 	fmt.Println("栈是否为空 =", isEmpty)
 }
 
 func TestLinkedListStack(t *testing.T) {
 	// 初始化栈
-	stack := NewLinkedListStack()
+	stack := newLinkedListStack()
 	// 元素入栈
-	stack.Push(1)
-	stack.Push(3)
-	stack.Push(2)
-	stack.Push(5)
-	stack.Push(4)
+	stack.push(1)
+	stack.push(3)
+	stack.push(2)
+	stack.push(5)
+	stack.push(4)
 	fmt.Print("栈 stack = ")
 	PrintList(stack.toList())
 
 	// 访问栈顶元素
-	peek := stack.Peek()
+	peek := stack.peek()
 	fmt.Println("栈顶元素 peek =", peek)
 
 	// 元素出栈
-	pop := stack.Pop()
+	pop := stack.pop()
 	fmt.Print("出栈元素 pop = ", pop, ", 出栈后 stack = ")
 	PrintList(stack.toList())
 
 	// 获取栈的长度
-	size := stack.Size()
+	size := stack.size()
 	fmt.Println("栈的长度 size =", size)
 
 	// 判断是否为空
-	isEmpty := stack.IsEmpty()
+	isEmpty := stack.isEmpty()
 	fmt.Println("栈是否为空 =", isEmpty)
 }
 
 // BenchmarkArrayStack 8 ns/op in Mac M1 Pro
 func BenchmarkArrayStack(b *testing.B) {
-	stack := NewArrayStack()
+	stack := newArrayStack()
 	// use b.N for looping
 	for i := 0; i < b.N; i++ {
-		stack.Push(777)
+		stack.push(777)
 	}
 	for i := 0; i < b.N; i++ {
-		stack.Pop()
+		stack.pop()
 	}
 }
 
 // BenchmarkLinkedListStack 65.02 ns/op in Mac M1 Pro
 func BenchmarkLinkedListStack(b *testing.B) {
-	stack := NewLinkedListStack()
+	stack := newLinkedListStack()
 	// use b.N for looping
 	for i := 0; i < b.N; i++ {
-		stack.Push(777)
+		stack.push(777)
 	}
 	for i := 0; i < b.N; i++ {
-		stack.Pop()
+		stack.pop()
 	}
 }

codes/go/chapter_tree/avl_tree.go

@@ -0,0 +1,211 @@
+// File: avl_tree.go
+// Created Time: 2023-01-08
+// Author: Reanon (793584285@qq.com)
+
+package chapter_tree
+
+import . "github.com/krahets/hello-algo/pkg"
+
+/* AVL Tree*/
+type avlTree struct {
+	// 根节点
+	root *TreeNode
+}
+
+func newAVLTree() *avlTree {
+	return &avlTree{root: nil}
+}
+
+/* 获取结点高度 */
+func height(node *TreeNode) int {
+	// 空结点高度为 -1 ，叶结点高度为 0
+	if node != nil {
+		return node.Height
+	}
+	return -1
+}
+
+/* 更新结点高度 */
+func updateHeight(node *TreeNode) {
+	lh := height(node.Left)
+	rh := height(node.Right)
+	// 结点高度等于最高子树高度 + 1
+	if lh > rh {
+		node.Height = lh + 1
+	} else {
+		node.Height = rh + 1
+	}
+}
+
+/* 获取平衡因子 */
+func balanceFactor(node *TreeNode) int {
+	// 空结点平衡因子为 0
+	if node == nil {
+		return 0
+	}
+	// 结点平衡因子 = 左子树高度 - 右子树高度
+	return height(node.Left) - height(node.Right)
+}
+
+/* 右旋操作 */
+func rightRotate(node *TreeNode) *TreeNode {
+	child := node.Left
+	grandChild := child.Right
+	// 以 child 为原点，将 node 向右旋转
+	child.Right = node
+	node.Left = grandChild
+	// 更新结点高度
+	updateHeight(node)
+	updateHeight(child)
+	// 返回旋转后子树的根节点
+	return child
+}
+
+/* 左旋操作 */
+func leftRotate(node *TreeNode) *TreeNode {
+	child := node.Right
+	grandChild := child.Left
+	// 以 child 为原点，将 node 向左旋转
+	child.Left = node
+	node.Right = grandChild
+	// 更新结点高度
+	updateHeight(node)
+	updateHeight(child)
+	// 返回旋转后子树的根节点
+	return child
+}
+
+/* 执行旋转操作，使该子树重新恢复平衡 */
+func rotate(node *TreeNode) *TreeNode {
+	// 获取结点 node 的平衡因子
+	// Go 推荐短变量，这里 bf 指代 balanceFactor
+	bf := balanceFactor(node)
+	// 左偏树
+	if bf > 1 {
+		if balanceFactor(node.Left) >= 0 {
+			// 右旋
+			return rightRotate(node)
+		} else {
+			// 先左旋后右旋
+			node.Left = leftRotate(node.Left)
+			return rightRotate(node)
+		}
+	}
+	// 右偏树
+	if bf < -1 {
+		if balanceFactor(node.Right) <= 0 {
+			// 左旋
+			return leftRotate(node)
+		} else {
+			// 先右旋后左旋
+			node.Right = rightRotate(node.Right)
+			return leftRotate(node)
+		}
+	}
+	// 平衡树，无需旋转，直接返回
+	return node
+}
+
+/* 插入结点 */
+func (t *avlTree) insert(val int) *TreeNode {
+	t.root = insertHelper(t.root, val)
+	return t.root
+}
+
+/* 递归插入结点（辅助函数） */
+func insertHelper(node *TreeNode, val int) *TreeNode {
+	if node == nil {
+		return NewTreeNode(val)
+	}
+	/* 1. 查找插入位置，并插入结点 */
+	if val < node.Val {
+		node.Left = insertHelper(node.Left, val)
+	} else if val > node.Val {
+		node.Right = insertHelper(node.Right, val)
+	} else {
+		// 重复结点不插入，直接返回
+		return node
+	}
+	// 更新结点高度
+	updateHeight(node)
+	/* 2. 执行旋转操作，使该子树重新恢复平衡 */
+	node = rotate(node)
+	// 返回子树的根节点
+	return node
+}
+
+/* 删除结点 */
+func (t *avlTree) remove(val int) *TreeNode {
+	root := removeHelper(t.root, val)
+	return root
+}
+
+/* 递归删除结点（辅助函数） */
+func removeHelper(node *TreeNode, val int) *TreeNode {
+	if node == nil {
+		return nil
+	}
+	/* 1. 查找结点，并删除之 */
+	if val < node.Val {
+		node.Left = removeHelper(node.Left, val)
+	} else if val > node.Val {
+		node.Right = removeHelper(node.Right, val)
+	} else {
+		if node.Left == nil || node.Right == nil {
+			child := node.Left
+			if node.Right != nil {
+				child = node.Right
+			}
+			// 子结点数量 = 0 ，直接删除 node 并返回
+			if child == nil {
+				return nil
+			} else {
+				// 子结点数量 = 1 ，直接删除 node
+				node = child
+			}
+		} else {
+			// 子结点数量 = 2 ，则将中序遍历的下个结点删除，并用该结点替换当前结点
+			temp := getInOrderNext(node.Right)
+			node.Right = removeHelper(node.Right, temp.Val)
+			node.Val = temp.Val
+		}
+	}
+	// 更新结点高度
+	updateHeight(node)
+	/* 2. 执行旋转操作，使该子树重新恢复平衡 */
+	node = rotate(node)
+	// 返回子树的根节点
+	return node
+}
+
+/* 获取中序遍历中的下一个结点（仅适用于 root 有左子结点的情况） */
+func getInOrderNext(node *TreeNode) *TreeNode {
+	if node == nil {
+		return node
+	}
+	// 循环访问左子结点，直到叶结点时为最小结点，跳出
+	for node.Left != nil {
+		node = node.Left
+	}
+	return node
+}
+
+/* 查找结点 */
+func (t *avlTree) search(val int) *TreeNode {
+	cur := t.root
+	// 循环查找，越过叶结点后跳出
+	for cur != nil {
+		// 目标结点在 root 的右子树中
+		if cur.Val < val {
+			cur = cur.Right
+		} else if cur.Val > val {
+			// 目标结点在 root 的左子树中
+			cur = cur.Left
+		} else {
+			// 找到目标结点，跳出循环
+			break
+		}
+	}
+	// 返回目标结点
+	return cur
+}

codes/go/chapter_tree/avl_tree_test.go

@@ -0,0 +1,54 @@
+// File: avl_tree_test.go
+// Created Time: 2023-01-08
+// Author: Reanon (793584285@qq.com)
+
+package chapter_tree
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
+)
+
+func TestAVLTree(t *testing.T) {
+	/* 初始化空 AVL 树 */
+	tree := newAVLTree()
+	/* 插入结点 */
+	// 请关注插入结点后，AVL 树是如何保持平衡的
+	testInsert(tree, 1)
+	testInsert(tree, 2)
+	testInsert(tree, 3)
+	testInsert(tree, 4)
+	testInsert(tree, 5)
+	testInsert(tree, 8)
+	testInsert(tree, 7)
+	testInsert(tree, 9)
+	testInsert(tree, 10)
+	testInsert(tree, 6)
+
+	/* 插入重复结点 */
+	testInsert(tree, 7)
+
+	/* 删除结点 */
+	// 请关注删除结点后，AVL 树是如何保持平衡的
+	testRemove(tree, 8) // 删除度为 0 的结点
+	testRemove(tree, 5) // 删除度为 1 的结点
+	testRemove(tree, 4) // 删除度为 2 的结点
+
+	/* 查询结点 */
+	node := tree.search(7)
+	fmt.Printf("\n查找到的结点对象为 %#v ，结点值 = %d \n", node, node.Val)
+}
+
+func testInsert(tree *avlTree, val int) {
+	tree.insert(val)
+	fmt.Printf("\n插入结点 %d 后，AVL 树为 \n", val)
+	PrintTree(tree.root)
+}
+
+func testRemove(tree *avlTree, val int) {
+	tree.remove(val)
+	fmt.Printf("\n删除结点  %d 后，AVL 树为 \n", val)
+	PrintTree(tree.root)
+}

codes/go/chapter_tree/binary_search_tree.go

@@ -10,26 +10,26 @@ import (
 	. "github.com/krahets/hello-algo/pkg"
 )
 
-type BinarySearchTree struct {
+type binarySearchTree struct {
 	root *TreeNode
 }
 
-func NewBinarySearchTree(nums []int) *BinarySearchTree {
+func newBinarySearchTree(nums []int) *binarySearchTree {
 	// sorting array
 	sort.Ints(nums)
 	root := buildBinarySearchTree(nums, 0, len(nums)-1)
-	return &BinarySearchTree{
+	return &binarySearchTree{
 		root: root,
 	}
 }
 
 /* 获取根结点 */
-func (bst *BinarySearchTree) GetRoot() *TreeNode {
+func (bst *binarySearchTree) getRoot() *TreeNode {
 	return bst.root
 }
 
 /* 获取中序遍历的下一个结点 */
-func (bst *BinarySearchTree) GetInOrderNext(node *TreeNode) *TreeNode {
+func (bst *binarySearchTree) getInOrderNext(node *TreeNode) *TreeNode {
 	if node == nil {
 		return node
 	}
@@ -41,7 +41,7 @@ func (bst *BinarySearchTree) GetInOrderNext(node *TreeNode) *TreeNode {
 }
 
 /* 查找结点 */
-func (bst *BinarySearchTree) Search(num int) *TreeNode {
+func (bst *binarySearchTree) search(num int) *TreeNode {
 	node := bst.root
 	// 循环查找，越过叶结点后跳出
 	for node != nil {
@@ -61,7 +61,7 @@ func (bst *BinarySearchTree) Search(num int) *TreeNode {
 }
 
 /* 插入结点 */
-func (bst *BinarySearchTree) Insert(num int) *TreeNode {
+func (bst *binarySearchTree) insert(num int) *TreeNode {
 	cur := bst.root
 	// 若树为空，直接提前返回
 	if cur == nil {
@@ -92,7 +92,7 @@ func (bst *BinarySearchTree) Insert(num int) *TreeNode {
 }
 
 /* 删除结点 */
-func (bst *BinarySearchTree) Remove(num int) *TreeNode {
+func (bst *binarySearchTree) remove(num int) *TreeNode {
 	cur := bst.root
 	// 若树为空，直接提前返回
 	if cur == nil {
@@ -136,10 +136,10 @@ func (bst *BinarySearchTree) Remove(num int) *TreeNode {
 		// 子结点数为 2
 	} else {
 		// 获取中序遍历中待删除结点 cur 的下一个结点
-		next := bst.GetInOrderNext(cur)
+		next := bst.getInOrderNext(cur)
 		temp := next.Val
 		// 递归删除结点 next
-		bst.Remove(next.Val)
+		bst.remove(next.Val)
 		// 将 next 的值复制给 cur
 		cur.Val = temp
 	}
@@ -160,7 +160,7 @@ func buildBinarySearchTree(nums []int, left, right int) *TreeNode {
 	return root
 }
 
-// Print binary search tree
-func (bst *BinarySearchTree) Print() {
+// print binary search tree
+func (bst *binarySearchTree) print() {
 	PrintTree(bst.root)
 }

codes/go/chapter_tree/binary_search_tree_test.go

@@ -11,31 +11,31 @@ import (
 
 func TestBinarySearchTree(t *testing.T) {
 	nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
-	bst := NewBinarySearchTree(nums)
+	bst := newBinarySearchTree(nums)
 	fmt.Println("\n初始化的二叉树为:")
-	bst.Print()
+	bst.print()
 
 	// 获取根结点
-	node := bst.GetRoot()
+	node := bst.getRoot()
 	fmt.Println("\n二叉树的根结点为:", node.Val)
 
 	// 查找结点
-	node = bst.Search(5)
+	node = bst.search(5)
 	fmt.Println("\n查找到的结点对象为", node, "，结点值 =", node.Val)
 
 	// 插入结点
-	node = bst.Insert(16)
+	node = bst.insert(16)
 	fmt.Println("\n插入结点后 16 的二叉树为:")
-	bst.Print()
+	bst.print()
 
 	// 删除结点
-	bst.Remove(1)
+	bst.remove(1)
 	fmt.Println("\n删除结点 1 后的二叉树为:")
-	bst.Print()
-	bst.Remove(2)
+	bst.print()
+	bst.remove(2)
 	fmt.Println("\n删除结点 2 后的二叉树为:")
-	bst.Print()
-	bst.Remove(4)
+	bst.print()
+	bst.remove(4)
 	fmt.Println("\n删除结点 4 后的二叉树为:")
-	bst.Print()
+	bst.print()
 }

codes/go/chapter_tree/binary_tree_bfs_test.go

@@ -14,11 +14,11 @@ import (
 func TestLevelOrder(t *testing.T) {
 	/* 初始化二叉树 */
 	// 这里借助了一个从数组直接生成二叉树的函数
-	root := ArrayToTree([]int{1, 2, 3, 4, 5, 6, 7})
-	fmt.Println("初始化二叉树: ")
+	root := ArrToTree([]any{1, 2, 3, 4, 5, 6, 7})
+	fmt.Println("\n初始化二叉树: ")
 	PrintTree(root)
 
 	// 层序遍历
 	nums := levelOrder(root)
-	fmt.Println("层序遍历的结点打印序列 =", nums)
+	fmt.Println("\n层序遍历的结点打印序列 =", nums)
 }

codes/go/chapter_tree/binary_tree_dfs_test.go

@@ -14,22 +14,22 @@ import (
 func TestPreInPostOrderTraversal(t *testing.T) {
 	/* 初始化二叉树 */
 	// 这里借助了一个从数组直接生成二叉树的函数
-	root := ArrayToTree([]int{1, 2, 3, 4, 5, 6, 7})
-	fmt.Println("初始化二叉树: ")
+	root := ArrToTree([]any{1, 2, 3, 4, 5, 6, 7})
+	fmt.Println("\n初始化二叉树: ")
 	PrintTree(root)
 
 	// 前序遍历
 	nums = nil
 	preOrder(root)
-	fmt.Println("前序遍历的结点打印序列 =", nums)
+	fmt.Println("\n前序遍历的结点打印序列 =", nums)
 
 	// 中序遍历
 	nums = nil
 	inOrder(root)
-	fmt.Println("中序遍历的结点打印序列 =", nums)
+	fmt.Println("\n中序遍历的结点打印序列 =", nums)
 
 	// 后序遍历
 	nums = nil
 	postOrder(root)
-	fmt.Println("后序遍历的结点打印序列 =", nums)
+	fmt.Println("\n后序遍历的结点打印序列 =", nums)
 }

codes/go/pkg/print_utils.go

@@ -76,7 +76,7 @@ func printTreeHelper(root *TreeNode, prev *trunk, isLeft bool) {
 	printTreeHelper(root.Left, trunk, false)
 }
 
-// trunk Help to Print tree structure
+// trunk Help to print tree structure
 type trunk struct {
 	prev *trunk
 	str  string
@@ -103,4 +103,4 @@ func PrintMap[K comparable, V any](m map[K]V) {
 	for key, value := range m {
 		fmt.Println(key, "->", value)
 	}
-}
+}

codes/go/pkg/tree_node.go

@@ -9,41 +9,48 @@ import (
 )
 
 type TreeNode struct {
-	Val   int
-	Left  *TreeNode
-	Right *TreeNode
+	Val    int       // 结点值
+	Height int       // 结点高度
+	Left   *TreeNode // 左子结点引用
+	Right  *TreeNode // 右子结点引用
 }
 
 func NewTreeNode(v int) *TreeNode {
 	return &TreeNode{
-		Left:  nil,
-		Right: nil,
-		Val:   v,
+		Val:    v,
+		Height: 0,
+		Left:   nil,
+		Right:  nil,
 	}
 }
 
-// ArrayToTree Generate a binary tree with an array
-func ArrayToTree(arr []int) *TreeNode {
+// ArrToTree Generate a binary tree given an array
+func ArrToTree(arr []any) *TreeNode {
 	if len(arr) <= 0 {
 		return nil
 	}
-	root := NewTreeNode(arr[0])
+	// TreeNode only accept integer value for now.
+	root := NewTreeNode(arr[0].(int))
 	// Let container.list as queue
 	queue := list.New()
 	queue.PushBack(root)
-	i := 1
+	i := 0
 	for queue.Len() > 0 {
 		// poll
 		node := queue.Remove(queue.Front()).(*TreeNode)
+		i++
 		if i < len(arr) {
-			node.Left = NewTreeNode(arr[i])
-			queue.PushBack(node.Left)
-			i++
+			if arr[i] != nil {
+				node.Left = NewTreeNode(arr[i].(int))
+				queue.PushBack(node.Left)
+			}
 		}
+		i++
 		if i < len(arr) {
-			node.Right = NewTreeNode(arr[i])
-			queue.PushBack(node.Right)
-			i++
+			if arr[i] != nil {
+				node.Right = NewTreeNode(arr[i].(int))
+				queue.PushBack(node.Right)
+			}
 		}
 	}
 	return root

codes/go/pkg/tree_node_test.go

@@ -10,8 +10,8 @@ import (
 )
 
 func TestTreeNode(t *testing.T) {
-	arr := []int{2, 3, 5, 6, 7}
-	node := ArrayToTree(arr)
+	arr := []any{1, 2, 3, nil, 5, 6, nil}
+	node := ArrToTree(arr)
 
 	// print tree
 	PrintTree(node)

codes/java/chapter_tree/binary_tree_bfs.java

@@ -30,8 +30,7 @@ public class binary_tree_bfs {
     public static void main(String[] args) {
         /* 初始化二叉树 */
         // 这里借助了一个从数组直接生成二叉树的函数
-        TreeNode root = TreeNode.arrToTree(new Integer[] {
-                1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null });
+        TreeNode root = TreeNode.arrToTree(new Integer[] { 1, 2, 3, 4, 5, 6, 7 });
         System.out.println("\n初始化二叉树\n");
         PrintUtil.printTree(root);
 

codes/java/chapter_tree/binary_tree_dfs.java

@@ -43,8 +43,7 @@ public class binary_tree_dfs {
     public static void main(String[] args) {
         /* 初始化二叉树 */
         // 这里借助了一个从数组直接生成二叉树的函数
-        TreeNode root = TreeNode.arrToTree(new Integer[] { 
-            1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null});
+        TreeNode root = TreeNode.arrToTree(new Integer[] { 1, 2, 3, 4, 5, 6, 7 });
         System.out.println("\n初始化二叉树\n");
         PrintUtil.printTree(root);
 

codes/java/include/PrintUtil.java

@@ -8,6 +8,7 @@ package include;
 
 import java.util.*;
 
+
 class Trunk {
     Trunk prev;
     String str;
@@ -103,4 +104,11 @@ public class PrintUtil {
             System.out.println(kv.getKey() + " -> " + kv.getValue());
         }
     }
+
+    public static void printHeap(PriorityQueue<Integer> queue) {
+        Integer[] nums = (Integer[])queue.toArray();
+        TreeNode root = TreeNode.arrToTree(nums);
+        
+        printTree(root);
+    }
 }

codes/java/include/TreeNode.java

@@ -22,7 +22,7 @@ public class TreeNode {
     }
 
     /**
-     * Generate a binary tree with an array
+     * Generate a binary tree given an array
      * @param arr
      * @return
      */
@@ -32,19 +32,19 @@ public class TreeNode {
         
         TreeNode root = new TreeNode(arr[0]);
         Queue<TreeNode> queue = new LinkedList<>() {{ add(root); }};
-        int i = 1;
+        int i = 0;
         while(!queue.isEmpty()) {
             TreeNode node = queue.poll();
+            if (++i >= arr.length) break;
             if(arr[i] != null) {
                 node.left = new TreeNode(arr[i]);
                 queue.add(node.left);
             }
-            i++;
+            if (++i >= arr.length) break;
             if(arr[i] != null) {
                 node.right = new TreeNode(arr[i]);
                 queue.add(node.right);
             }
-            i++;
         }
         return root;
     }
@@ -71,20 +71,4 @@ public class TreeNode {
         }
         return list;
     }
-    
-    /**
-     * Get a tree node with specific value in a binary tree
-     * @param root
-     * @param val
-     * @return
-     */
-    public static TreeNode getTreeNode(TreeNode root, int val) {
-        if (root == null)
-            return null;
-        if (root.val == val)
-            return root;
-        TreeNode left = getTreeNode(root.left, val);
-        TreeNode right = getTreeNode(root.right, val);
-        return left != null ? left : right;
-    }
 }

codes/javascript/chapter_tree/binary_tree_bfs.js

@@ -28,10 +28,10 @@ function hierOrder(root) {
 /* Driver Code */
 /* 初始化二叉树 */
 // 这里借助了一个从数组直接生成二叉树的函数
-var root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null]);
+var root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
 console.log("\n初始化二叉树\n");
 printTree(root);
 
 /* 层序遍历 */
 let list = hierOrder(root);
-console.log("\n层序遍历的结点打印序列 = " + list);
+console.log("\n层序遍历的结点打印序列 = " + list);

codes/javascript/chapter_tree/binary_tree_dfs.js

@@ -40,7 +40,7 @@ function postOrder(root) {
 /* Driver Code */
 /* 初始化二叉树 */
 // 这里借助了一个从数组直接生成二叉树的函数
-var root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null]);
+var root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
 console.log("\n初始化二叉树\n");
 printTree(root);
 
@@ -58,4 +58,3 @@ console.log("\n中序遍历的结点打印序列 = " + list);
 list.length = 0;
 postOrder(root);
 console.log("\n后序遍历的结点打印序列 = " + list);
-

codes/javascript/include/TreeNode.js

@@ -14,7 +14,7 @@ function TreeNode(val, left, right) {
 }
 
 /**
-* Generate a binary tree with an array
+* Generate a binary tree given an array
 * @param arr
 * @return
 */
@@ -24,20 +24,21 @@ function arrToTree(arr) {
          
     let root = new TreeNode(arr[0]);
     let queue = [root] 
-    let i = 1;
-    while(queue.length) {
+    let i = 0;
+    while (queue.length) {
         let node = queue.shift();
-        if(arr[i] !== null) {
+        if (++i >= arr.length) break;
+        if (arr[i] !== null) {
             node.left = new TreeNode(arr[i]);
             queue.push(node.left);
         }
-        i++;
-        if(arr[i] !== null) {
+        if (++i >= arr.length) break;
+        if (arr[i] !== null) {
             node.right = new TreeNode(arr[i]);
             queue.push(node.right);
         }
-        i++;
     }
+
     return root;
 }
 

codes/python/chapter_tree/avl_tree.py

@@ -5,30 +5,28 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
-import typing
-
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from include import *
 
 
 class AVLTree:
-    def __init__(self, root: typing.Optional[TreeNode] = None):
+    def __init__(self, root: Optional[TreeNode] = None):
         self.root = root
 
     """ 获取结点高度 """
-    def height(self, node: typing.Optional[TreeNode]) -> int:
+    def height(self, node: Optional[TreeNode]) -> int:
         # 空结点高度为 -1 ，叶结点高度为 0
         if node is not None:
             return node.height
         return -1
 
     """ 更新结点高度 """
-    def __update_height(self, node: TreeNode):
+    def __update_height(self, node: Optional[TreeNode]):
         # 结点高度等于最高子树高度 + 1
         node.height = max([self.height(node.left), self.height(node.right)]) + 1
 
     """ 获取平衡因子 """
-    def balance_factor(self, node: TreeNode) -> int:
+    def balance_factor(self, node: Optional[TreeNode]) -> int:
         # 空结点平衡因子为 0
         if node is None:
             return 0
@@ -36,7 +34,7 @@ class AVLTree:
         return self.height(node.left) - self.height(node.right)
 
     """ 右旋操作 """
-    def __right_rotate(self, node: TreeNode) -> TreeNode:
+    def __right_rotate(self, node: Optional[TreeNode]) -> TreeNode:
         child = node.left
         grand_child = child.right
         # 以 child 为原点，将 node 向右旋转
@@ -49,7 +47,7 @@ class AVLTree:
         return child
 
     """ 左旋操作 """
-    def __left_rotate(self, node: TreeNode) -> TreeNode:
+    def __left_rotate(self, node: Optional[TreeNode]) -> TreeNode:
         child = node.right
         grand_child = child.left
         # 以 child 为原点，将 node 向左旋转
@@ -62,7 +60,7 @@ class AVLTree:
         return child
 
     """ 执行旋转操作，使该子树重新恢复平衡 """
-    def __rotate(self, node: TreeNode) -> TreeNode:
+    def __rotate(self, node: Optional[TreeNode]) -> TreeNode:
         # 获取结点 node 的平衡因子
         balance_factor = self.balance_factor(node)
         # 左偏树
@@ -92,7 +90,7 @@ class AVLTree:
         return self.root
 
     """ 递归插入结点（辅助函数）"""
-    def __insert_helper(self, node: typing.Optional[TreeNode], val: int) -> TreeNode:
+    def __insert_helper(self, node: Optional[TreeNode], val: int) -> TreeNode:
         if node is None:
             return TreeNode(val)
         # 1. 查找插入位置，并插入结点
@@ -114,7 +112,7 @@ class AVLTree:
         return root
 
     """ 递归删除结点（辅助函数） """
-    def __remove_helper(self, node: typing.Optional[TreeNode], val: int) -> typing.Optional[TreeNode]:
+    def __remove_helper(self, node: Optional[TreeNode], val: int) -> Optional[TreeNode]:
         if node is None:
             return None
         # 1. 查找结点，并删除之
@@ -141,7 +139,7 @@ class AVLTree:
         return self.__rotate(node)
 
     """ 获取中序遍历中的下一个结点（仅适用于 root 有左子结点的情况） """
-    def __get_inorder_next(self, node: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
+    def __get_inorder_next(self, node: Optional[TreeNode]) -> Optional[TreeNode]:
         if node is None:
             return None
         # 循环访问左子结点，直到叶结点时为最小结点，跳出

codes/python/chapter_tree/binary_search_tree.py

@@ -5,20 +5,18 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
-import typing
-
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from include import *
 
 
 """ 二叉搜索树 """
 class BinarySearchTree:
-    def __init__(self, nums: typing.List[int]) -> None:
+    def __init__(self, nums: List[int]) -> None:
         nums.sort()
         self.__root = self.build_tree(nums, 0, len(nums) - 1)
 
     """ 构建二叉搜索树 """
-    def build_tree(self, nums: typing.List[int], start_index: int, end_index: int) -> typing.Optional[TreeNode]:
+    def build_tree(self, nums: List[int], start_index: int, end_index: int) -> Optional[TreeNode]:
         if start_index > end_index:
             return None
 
@@ -31,11 +29,11 @@ class BinarySearchTree:
         return root
 
     @property
-    def root(self) -> typing.Optional[TreeNode]:
+    def root(self) -> Optional[TreeNode]:
         return self.__root
 
     """ 查找结点 """
-    def search(self, num: int) -> typing.Optional[TreeNode]:
+    def search(self, num: int) -> Optional[TreeNode]:
         cur = self.root
         # 循环查找，越过叶结点后跳出
         while cur is not None:
@@ -51,7 +49,7 @@ class BinarySearchTree:
         return cur
 
     """ 插入结点 """
-    def insert(self, num: int) -> typing.Optional[TreeNode]:
+    def insert(self, num: int) -> Optional[TreeNode]:
         root = self.root
         # 若树为空，直接提前返回
         if root is None:
@@ -81,7 +79,7 @@ class BinarySearchTree:
         return node
 
     """ 删除结点 """
-    def remove(self, num: int) -> typing.Optional[TreeNode]:
+    def remove(self, num: int) -> Optional[TreeNode]:
         root = self.root
         # 若树为空，直接提前返回
         if root is None:
@@ -126,7 +124,7 @@ class BinarySearchTree:
         return cur
 
     """ 获取中序遍历中的下一个结点（仅适用于 root 有左子结点的情况） """
-    def get_inorder_next(self, root: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
+    def get_inorder_next(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
         if root is None:
             return root
         # 循环访问左子结点，直到叶结点时为最小结点，跳出
@@ -138,7 +136,7 @@ class BinarySearchTree:
 """ Driver Code """
 if __name__ == "__main__":
     # 初始化二叉搜索树
-    nums = list(range(1, 16))
+    nums = list(range(1, 16)) # [1, 2, ..., 15]
     bst = BinarySearchTree(nums=nums)
     print("\n初始化的二叉树为\n")
     print_tree(bst.root)

codes/python/chapter_tree/binary_tree.py

@@ -36,5 +36,5 @@ if __name__ == "__main__":
     print_tree(n1)
     # 删除结点
     n1.left = n2
-    print("\n删除结点 P 后\n");
+    print("\n删除结点 P 后\n")
     print_tree(n1)

codes/python/chapter_tree/binary_tree_bfs.py

@@ -5,14 +5,12 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
-import typing
-
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from include import *
 
 
 """ 层序遍历 """
-def hier_order(root: TreeNode):
+def hier_order(root: Optional[TreeNode]):
     # 初始化队列，加入根结点
     queue = collections.deque()
     queue.append(root)
@@ -32,7 +30,7 @@ def hier_order(root: TreeNode):
 if __name__ == "__main__":
     # 初始化二叉树
     # 这里借助了一个从数组直接生成二叉树的函数
-    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
+    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
     print("\n初始化二叉树\n")
     print_tree(root)
 

codes/python/chapter_tree/binary_tree_dfs.py

@@ -5,8 +5,6 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
-import typing
-
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from include import *
 
@@ -14,7 +12,7 @@ from include import *
 res = []
 
 """ 前序遍历 """
-def pre_order(root: typing.Optional[TreeNode]):
+def pre_order(root: Optional[TreeNode]):
     if root is None:
         return
     # 访问优先级：根结点 -> 左子树 -> 右子树
@@ -23,7 +21,7 @@ def pre_order(root: typing.Optional[TreeNode]):
     pre_order(root=root.right)
 
 """ 中序遍历 """
-def in_order(root: typing.Optional[TreeNode]):
+def in_order(root: Optional[TreeNode]):
     if root is None:
         return
     # 访问优先级：左子树 -> 根结点 -> 右子树
@@ -32,7 +30,7 @@ def in_order(root: typing.Optional[TreeNode]):
     in_order(root=root.right)
 
 """ 后序遍历 """
-def post_order(root: typing.Optional[TreeNode]):
+def post_order(root: Optional[TreeNode]):
     if root is None:
         return
     # 访问优先级：左子树 -> 右子树 -> 根结点
@@ -45,7 +43,7 @@ def post_order(root: typing.Optional[TreeNode]):
 if __name__ == "__main__":
     # 初始化二叉树
     # 这里借助了一个从数组直接生成二叉树的函数
-    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
+    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
     print("\n初始化二叉树\n")
     print_tree(root)
 

codes/python/include/__init__.py

@@ -4,7 +4,7 @@ import queue
 import random
 import functools
 import collections
-from typing import List
+from typing import Optional, List, Dict, DefaultDict, OrderedDict, Set, Deque
 from .linked_list import ListNode, list_to_linked_list, linked_list_to_list, get_list_node
 from .binary_tree import TreeNode, list_to_tree, tree_to_list, get_tree_node
 from .print_util import print_matrix, print_linked_list, print_tree, print_dict

codes/python/include/binary_tree.py

@@ -26,39 +26,30 @@ class TreeNode:
 
 def list_to_tree(arr):
     """Generate a binary tree with a list
-
-    Args:
-        arr ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """
     if not arr:
         return None
-    i = 1
-    root = TreeNode(int(arr[0]))
-    queue = collections.deque()
-    queue.append(root)
+    
+    i = 0
+    root = TreeNode(arr[0])
+    queue = collections.deque([root])
     while queue:
         node = queue.popleft()
+        i += 1
+        if i >= len(arr): break
         if arr[i] != None:
-            node.left = TreeNode(int(arr[i]))
+            node.left = TreeNode(arr[i])
             queue.append(node.left)
         i += 1
+        if i >= len(arr): break
         if arr[i] != None:
-            node.right = TreeNode(int(arr[i]))
+            node.right = TreeNode(arr[i])
             queue.append(node.right)
-        i += 1
+            
     return root
 
 def tree_to_list(root):
     """Serialize a tree into an array
-
-    Args:
-        root ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """    
     if not root: return []
     queue = collections.deque()
@@ -75,13 +66,6 @@ def tree_to_list(root):
 
 def get_tree_node(root, val):
     """Get a tree node with specific value in a binary tree
-
-    Args:
-        root ([type]): [description]
-        val ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """    
     if not root:
         return

codes/swift/Package.swift

@@ -9,6 +9,8 @@ let package = Package(
         .executable(name: "worst_best_time_complexity", targets: ["worst_best_time_complexity"]),
         .executable(name: "space_complexity", targets: ["space_complexity"]),
         .executable(name: "leetcode_two_sum", targets: ["leetcode_two_sum"]),
+        .executable(name: "array", targets: ["array"]),
+        .executable(name: "linked_list", targets: ["linked_list"]),
     ],
     targets: [
         .target(name: "utils", path: "utils"),
@@ -16,5 +18,7 @@ let package = Package(
         .executableTarget(name: "worst_best_time_complexity", path: "chapter_computational_complexity", sources: ["worst_best_time_complexity.swift"]),
         .executableTarget(name: "space_complexity", dependencies: ["utils"], path: "chapter_computational_complexity", sources: ["space_complexity.swift"]),
         .executableTarget(name: "leetcode_two_sum", path: "chapter_computational_complexity", sources: ["leetcode_two_sum.swift"]),
+        .executableTarget(name: "array", path: "chapter_array_and_linkedlist", sources: ["array.swift"]),
+        .executableTarget(name: "linked_list", dependencies: ["utils"], path: "chapter_array_and_linkedlist", sources: ["linked_list.swift"]),
     ]
 )

codes/swift/chapter_array_and_linkedlist/array.swift

@@ -0,0 +1,103 @@
+/**
+ * File: array.swift
+ * Created Time: 2023-01-05
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+/* 随机返回一个数组元素 */
+func randomAccess(nums: [Int]) -> Int {
+    // 在区间 [0, nums.count) 中随机抽取一个数字
+    let randomIndex = nums.indices.randomElement()!
+    // 获取并返回随机元素
+    let randomNum = nums[randomIndex]
+    return randomNum
+}
+
+/* 扩展数组长度 */
+func extend(nums: [Int], enlarge: Int) -> [Int] {
+    // 初始化一个扩展长度后的数组
+    var res = Array(repeating: 0, count: nums.count + enlarge)
+    // 将原数组中的所有元素复制到新数组
+    for i in nums.indices {
+        res[i] = nums[i]
+    }
+    // 返回扩展后的新数组
+    return res
+}
+
+/* 在数组的索引 index 处插入元素 num */
+func insert(nums: inout [Int], num: Int, index: Int) {
+    // 把索引 index 以及之后的所有元素向后移动一位
+    for i in sequence(first: nums.count - 1, next: { $0 > index + 1 ? $0 - 1 : nil }) {
+        nums[i] = nums[i - 1]
+    }
+    // 将 num 赋给 index 处元素
+    nums[index] = num
+}
+
+/* 删除索引 index 处元素 */
+func remove(nums: inout [Int], index: Int) {
+    let count = nums.count
+    // 把索引 index 之后的所有元素向前移动一位
+    for i in sequence(first: index, next: { $0 < count - 1 - 1 ? $0 + 1 : nil }) {
+        nums[i] = nums[i + 1]
+    }
+}
+
+/* 遍历数组 */
+func traverse(nums: [Int]) {
+    var count = 0
+    // 通过索引遍历数组
+    for _ in nums.indices {
+        count += 1
+    }
+    // 直接遍历数组
+    for _ in nums {
+        count += 1
+    }
+}
+
+/* 在数组中查找指定元素 */
+func find(nums: [Int], target: Int) -> Int {
+    for i in nums.indices {
+        if nums[i] == target {
+            return i
+        }
+    }
+    return -1
+}
+
+@main
+enum _Array {
+    /* Driver Code */
+    static func main() {
+        /* 初始化数组 */
+        let arr = Array(repeating: 0, count: 5)
+        print("数组 arr = \(arr)")
+        var nums = [1, 3, 2, 5, 4]
+        print("数组 nums = \(nums)")
+
+        /* 随机访问 */
+        let randomNum = randomAccess(nums: nums)
+        print("在 nums 中获取随机元素 \(randomNum)")
+
+        /* 长度扩展 */
+        nums = extend(nums: nums, enlarge: 3)
+        print("将数组长度扩展至 8 ，得到 nums = \(nums)")
+
+        /* 插入元素 */
+        insert(nums: &nums, num: 6, index: 3)
+        print("在索引 3 处插入数字 6 ，得到 nums = \(nums)")
+
+        /* 删除元素 */
+        remove(nums: &nums, index: 2)
+        print("删除索引 2 处的元素，得到 nums = \(nums)")
+
+        /* 遍历数组 */
+        traverse(nums: nums)
+
+        /* 查找元素 */
+        let index = find(nums: nums, target: 3)
+        print("在 nums 中查找元素 3 ，得到索引 = \(index)")
+    }
+}

codes/swift/chapter_array_and_linkedlist/linked_list.swift

@@ -0,0 +1,91 @@
+/**
+ * File: linked_list.swift
+ * Created Time: 2023-01-08
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+import utils
+
+/* 在链表的结点 n0 之后插入结点 P */
+func insert(n0: ListNode, P: ListNode) {
+    let n1 = n0.next
+    n0.next = P
+    P.next = n1
+}
+
+/* 删除链表的结点 n0 之后的首个结点 */
+func remove(n0: ListNode) {
+    if n0.next == nil {
+        return
+    }
+    // n0 -> P -> n1
+    let P = n0.next
+    let n1 = P?.next
+    n0.next = n1
+    P?.next = nil
+}
+
+/* 访问链表中索引为 index 的结点 */
+func access(head: ListNode, index: Int) -> ListNode? {
+    var head: ListNode? = head
+    for _ in 0 ..< index {
+        head = head?.next
+        if head == nil {
+            return nil
+        }
+    }
+    return head
+}
+
+/* 在链表中查找值为 target 的首个结点 */
+func find(head: ListNode, target: Int) -> Int {
+    var head: ListNode? = head
+    var index = 0
+    while head != nil {
+        if head?.val == target {
+            return index
+        }
+        head = head?.next
+        index += 1
+    }
+    return -1
+}
+
+@main
+enum LinkedList {
+    /* Driver Code */
+    static func main() {
+        /* 初始化链表 */
+        // 初始化各个结点
+        let n0 = ListNode(x: 1)
+        let n1 = ListNode(x: 3)
+        let n2 = ListNode(x: 2)
+        let n3 = ListNode(x: 5)
+        let n4 = ListNode(x: 4)
+        // 构建引用指向
+        n0.next = n1
+        n1.next = n2
+        n2.next = n3
+        n3.next = n4
+        print("初始化的链表为")
+        PrintUtil.printLinkedList(head: n0)
+
+        /* 插入结点 */
+        insert(n0: n0, P: ListNode(x: 0))
+        print("插入结点后的链表为")
+        PrintUtil.printLinkedList(head: n0)
+
+        /* 删除结点 */
+        remove(n0: n0)
+        print("删除结点后的链表为")
+        PrintUtil.printLinkedList(head: n0)
+
+        /* 访问结点 */
+        let node = access(head: n0, index: 3)
+        print("链表中索引 3 处的结点的值 = \(node!.val)")
+
+        /* 查找结点 */
+        let index = find(head: n0, target: 2)
+        print("链表中值为 2 的结点的索引 = \(index)")
+    }
+}

codes/swift/chapter_computational_complexity/space_complexity.swift

@@ -6,14 +6,14 @@
 
 import utils
 
-// 函数
+/* 函数 */
 @discardableResult
 func function() -> Int {
     // do something
     return 0
 }
 
-// 常数阶
+/* 常数阶 */
 func constant(n: Int) {
     // 常量、变量、对象占用 O(1) 空间
     let a = 0
@@ -30,7 +30,7 @@ func constant(n: Int) {
     }
 }
 
-// 线性阶
+/* 线性阶 */
 func linear(n: Int) {
     // 长度为 n 的数组占用 O(n) 空间
     let nums = Array(repeating: 0, count: n)
@@ -40,7 +40,7 @@ func linear(n: Int) {
     let map = Dictionary(uniqueKeysWithValues: (0 ..< n).map { ($0, "\($0)") })
 }
 
-// 线性阶（递归实现）
+/* 线性阶（递归实现） */
 func linearRecur(n: Int) {
     print("递归 n = \(n)")
     if n == 1 {
@@ -49,13 +49,13 @@ func linearRecur(n: Int) {
     linearRecur(n: n - 1)
 }
 
-// 平方阶
+/* 平方阶 */
 func quadratic(n: Int) {
     // 二维列表占用 O(n^2) 空间
     let numList = Array(repeating: Array(repeating: 0, count: n), count: n)
 }
 
-// 平方阶（递归实现）
+/* 平方阶（递归实现） */
 @discardableResult
 func quadraticRecur(n: Int) -> Int {
     if n <= 0 {
@@ -67,7 +67,7 @@ func quadraticRecur(n: Int) -> Int {
     return quadraticRecur(n: n - 1)
 }
 
-// 指数阶（建立满二叉树）
+/* 指数阶（建立满二叉树） */
 func buildTree(n: Int) -> TreeNode? {
     if n == 0 {
         return nil
@@ -80,7 +80,7 @@ func buildTree(n: Int) -> TreeNode? {
 
 @main
 enum SpaceComplexity {
-    // Driver Code
+    /* Driver Code */
     static func main() {
         let n = 5
         // 常数阶

codes/swift/chapter_computational_complexity/time_complexity.swift

@@ -4,7 +4,7 @@
  * Author: nuomi1 (nuomi1@qq.com)
  */
 
-// 常数阶
+/* 常数阶 */
 func constant(n: Int) -> Int {
     var count = 0
     let size = 100_000
@@ -14,7 +14,7 @@ func constant(n: Int) -> Int {
     return count
 }
 
-// 线性阶
+/* 线性阶 */
 func linear(n: Int) -> Int {
     var count = 0
     for _ in 0 ..< n {
@@ -23,7 +23,7 @@ func linear(n: Int) -> Int {
     return count
 }
 
-// 线性阶（遍历数组）
+/* 线性阶（遍历数组） */
 func arrayTraversal(nums: [Int]) -> Int {
     var count = 0
     // 循环次数与数组长度成正比
@@ -33,7 +33,7 @@ func arrayTraversal(nums: [Int]) -> Int {
     return count
 }
 
-// 平方阶
+/* 平方阶 */
 func quadratic(n: Int) -> Int {
     var count = 0
     // 循环次数与数组长度成平方关系
@@ -45,7 +45,7 @@ func quadratic(n: Int) -> Int {
     return count
 }
 
-// 平方阶（冒泡排序）
+/* 平方阶（冒泡排序） */
 func bubbleSort(nums: inout [Int]) -> Int {
     var count = 0 // 计数器
     // 外循环：待排序元素数量为 n-1, n-2, ..., 1
@@ -64,7 +64,7 @@ func bubbleSort(nums: inout [Int]) -> Int {
     return count
 }
 
-// 指数阶（循环实现）
+/* 指数阶（循环实现） */
 func exponential(n: Int) -> Int {
     var count = 0
     var base = 1
@@ -79,7 +79,7 @@ func exponential(n: Int) -> Int {
     return count
 }
 
-// 指数阶（递归实现）
+/* 指数阶（递归实现） */
 func expRecur(n: Int) -> Int {
     if n == 1 {
         return 1
@@ -87,7 +87,7 @@ func expRecur(n: Int) -> Int {
     return expRecur(n: n - 1) + expRecur(n: n - 1) + 1
 }
 
-// 对数阶（循环实现）
+/* 对数阶（循环实现） */
 func logarithmic(n: Int) -> Int {
     var count = 0
     var n = n
@@ -98,7 +98,7 @@ func logarithmic(n: Int) -> Int {
     return count
 }
 
-// 对数阶（递归实现）
+/* 对数阶（递归实现） */
 func logRecur(n: Int) -> Int {
     if n <= 1 {
         return 0
@@ -106,7 +106,7 @@ func logRecur(n: Int) -> Int {
     return logRecur(n: n / 2) + 1
 }
 
-// 线性对数阶
+/* 线性对数阶 */
 func linearLogRecur(n: Double) -> Int {
     if n <= 1 {
         return 1
@@ -118,7 +118,7 @@ func linearLogRecur(n: Double) -> Int {
     return count
 }
 
-// 阶乘阶（递归实现）
+/* 阶乘阶（递归实现） */
 func factorialRecur(n: Int) -> Int {
     if n == 0 {
         return 1
@@ -133,39 +133,40 @@ func factorialRecur(n: Int) -> Int {
 
 @main
 enum TimeComplexity {
+    /* Driver Code */
     static func main() {
         // 可以修改 n 运行，体会一下各种复杂度的操作数量变化趋势
         let n = 8
-        print("输入数据大小 n =", n)
+        print("输入数据大小 n = \(n)")
 
         var count = constant(n: n)
-        print("常数阶的计算操作数量 =", count)
+        print("常数阶的计算操作数量 = \(count)")
 
         count = linear(n: n)
-        print("线性阶的计算操作数量 =", count)
+        print("线性阶的计算操作数量 = \(count)")
         count = arrayTraversal(nums: Array(repeating: 0, count: n))
-        print("线性阶（遍历数组）的计算操作数量 =", count)
+        print("线性阶（遍历数组）的计算操作数量 = \(count)")
 
         count = quadratic(n: n)
-        print("平方阶的计算操作数量 =", count)
+        print("平方阶的计算操作数量 = \(count)")
         var nums = Array(sequence(first: n, next: { $0 > 0 ? $0 - 1 : nil })) // [n,n-1,...,2,1]
         count = bubbleSort(nums: &nums)
-        print("平方阶（冒泡排序）的计算操作数量 =", count)
+        print("平方阶（冒泡排序）的计算操作数量 = \(count)")
 
         count = exponential(n: n)
-        print("指数阶（循环实现）的计算操作数量 =", count)
+        print("指数阶（循环实现）的计算操作数量 = \(count)")
         count = expRecur(n: n)
-        print("指数阶（递归实现）的计算操作数量 =", count)
+        print("指数阶（递归实现）的计算操作数量 = \(count)")
 
         count = logarithmic(n: n)
-        print("对数阶（循环实现）的计算操作数量 =", count)
+        print("对数阶（循环实现）的计算操作数量 = \(count)")
         count = logRecur(n: n)
-        print("对数阶（递归实现）的计算操作数量 =", count)
+        print("对数阶（递归实现）的计算操作数量 = \(count)")
 
         count = linearLogRecur(n: Double(n))
-        print("线性对数阶（递归实现）的计算操作数量 =", count)
+        print("线性对数阶（递归实现）的计算操作数量 = \(count)")
 
         count = factorialRecur(n: n)
-        print("阶乘阶（递归实现）的计算操作数量 =", count)
+        print("阶乘阶（递归实现）的计算操作数量 = \(count)")
     }
 }

codes/swift/chapter_computational_complexity/worst_best_time_complexity.swift

@@ -4,7 +4,7 @@
  * Author: nuomi1 (nuomi1@qq.com)
  */
 
-// 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱
+/* 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱 */
 func randomNumbers(n: Int) -> [Int] {
     // 生成数组 nums = { 1, 2, 3, ..., n }
     var nums = Array(1 ... n)
@@ -13,7 +13,7 @@ func randomNumbers(n: Int) -> [Int] {
     return nums
 }
 
-// 查找数组 nums 中数字 1 所在索引
+/* 查找数组 nums 中数字 1 所在索引 */
 func findOne(nums: [Int]) -> Int {
     for i in nums.indices {
         if nums[i] == 1 {
@@ -25,14 +25,14 @@ func findOne(nums: [Int]) -> Int {
 
 @main
 enum WorstBestTimeComplexity {
-    // Driver Code
+    /* Driver Code */
     static func main() {
         for _ in 0 ..< 10 {
             let n = 100
             let nums = randomNumbers(n: n)
             let index = findOne(nums: nums)
-            print("数组 [ 1, 2, ..., n ] 被打乱后 =", nums)
-            print("数字 1 的索引为", index)
+            print("数组 [ 1, 2, ..., n ] 被打乱后 = \(nums)")
+            print("数字 1 的索引为 \(index)")
         }
     }
 }

codes/swift/utils/PrintUtil.swift

@@ -15,6 +15,16 @@ public enum PrintUtil {
         }
     }
 
+    public static func printLinkedList(head: ListNode) {
+        var head: ListNode? = head
+        var list: [String] = []
+        while head != nil {
+            list.append("\(head!.val)")
+            head = head?.next
+        }
+        print(list.joined(separator: " -> "))
+    }
+
     public static func printTree(root: TreeNode?) {
         printTree(root: root, prev: nil, isLeft: false)
     }

codes/typescript/chapter_tree/binary_tree_bfs.ts

@@ -30,7 +30,7 @@ function hierOrder(root: TreeNode | null): number[] {
 /* Driver Code */
 /* 初始化二叉树 */
 // 这里借助了一个从数组直接生成二叉树的函数
-var root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null]);
+var root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
 console.log('\n初始化二叉树\n');
 printTree(root);
 

codes/typescript/chapter_tree/binary_tree_dfs.ts

@@ -47,7 +47,7 @@ function postOrder(root: TreeNode | null): void {
 /* Driver Code */
 /* 初始化二叉树 */
 // 这里借助了一个从数组直接生成二叉树的函数
-const root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null]);
+const root = arrToTree([1, 2, 3, 4, 5, 6, 7]);
 console.log('\n初始化二叉树\n');
 printTree(root);
 

codes/typescript/module/TreeNode.ts

@@ -20,7 +20,7 @@ class TreeNode {
 }
 
 /**
- * Generate a binary tree with an array
+ * Generate a binary tree given an array
  * @param arr
  * @return
  */
@@ -31,19 +31,19 @@ function arrToTree(arr: (number | null)[]): TreeNode | null {
 
     const root = new TreeNode(arr[0] as number);
     const queue = [root];
-    let i = 1;
+    let i = 0;
     while (queue.length) {
         let node = queue.shift() as TreeNode;
+        if (++i >= arr.length) break;
         if (arr[i] !== null) {
             node.left = new TreeNode(arr[i] as number);
             queue.push(node.left);
         }
-        i++;
+        if (++i >= arr.length) break;
         if (arr[i] !== null) {
             node.right = new TreeNode(arr[i] as number);
             queue.push(node.right);
         }
-        i++;
     }
     return root;
 }

codes/zig/.gitignore

@@ -0,0 +1,2 @@
+zig-cache/
+zig-out/

codes/zig/build.zig

@@ -0,0 +1,46 @@
+const std = @import("std");
+
+// zig version 0.10.0
+pub fn build(b: *std.build.Builder) void {
+    const target = b.standardTargetOptions(.{});
+    const mode = b.standardReleaseOptions();
+
+    // "chapter_computational_complexity/time_complexity.zig"
+    // Run Command: zig build run_time_complexity
+    const exe_time_complexity = b.addExecutable("time_complexity", "chapter_computational_complexity/time_complexity.zig");
+    exe_time_complexity.addPackagePath("include", "include/include.zig");
+    exe_time_complexity.setTarget(target);
+    exe_time_complexity.setBuildMode(mode);
+    exe_time_complexity.install();
+    const run_cmd_time_complexity = exe_time_complexity.run();
+    run_cmd_time_complexity.step.dependOn(b.getInstallStep());
+    if (b.args) |args| run_cmd_time_complexity.addArgs(args);
+    const run_step_time_complexity = b.step("run_time_complexity", "Run time_complexity");
+    run_step_time_complexity.dependOn(&run_cmd_time_complexity.step);
+
+    // "chapter_computational_complexity/worst_best_time_complexity.zig"
+    // Run Command: zig build run_worst_best_time_complexity
+    const exe_worst_best_time_complexity = b.addExecutable("worst_best_time_complexity", "chapter_computational_complexity/worst_best_time_complexity.zig");
+    exe_worst_best_time_complexity.addPackagePath("include", "include/include.zig");
+    exe_worst_best_time_complexity.setTarget(target);
+    exe_worst_best_time_complexity.setBuildMode(mode);
+    exe_worst_best_time_complexity.install();
+    const run_cmd_worst_best_time_complexity = exe_worst_best_time_complexity.run();
+    run_cmd_worst_best_time_complexity.step.dependOn(b.getInstallStep());
+    if (b.args) |args| run_cmd_worst_best_time_complexity.addArgs(args);
+    const run_step_worst_best_time_complexity = b.step("run_worst_best_time_complexity", "Run worst_best_time_complexity");
+    run_step_worst_best_time_complexity.dependOn(&run_cmd_worst_best_time_complexity.step);
+
+    // "chapter_computational_complexity/leetcode_two_sum.zig"
+    // Run Command: zig build run_leetcode_two_sum
+    const exe_leetcode_two_sum = b.addExecutable("leetcode_two_sum", "chapter_computational_complexity/leetcode_two_sum.zig");
+    exe_leetcode_two_sum.addPackagePath("include", "include/include.zig");
+    exe_leetcode_two_sum.setTarget(target);
+    exe_leetcode_two_sum.setBuildMode(mode);
+    exe_leetcode_two_sum.install();
+    const run_cmd_leetcode_two_sum = exe_leetcode_two_sum.run();
+    run_cmd_leetcode_two_sum.step.dependOn(b.getInstallStep());
+    if (b.args) |args| run_cmd_leetcode_two_sum.addArgs(args);
+    const run_step_leetcode_two_sum = b.step("run_leetcode_two_sum", "Run leetcode_two_sum");
+    run_step_leetcode_two_sum.dependOn(&run_cmd_leetcode_two_sum.step);
+}

codes/zig/chapter_computational_complexity/leetcode_two_sum.zig

@@ -0,0 +1,61 @@
+// File: leetcode_two_sum.zig
+// Created Time: 2023-01-07
+// Author: sjinzh (sjinzh@gmail.com)
+
+const std = @import("std");
+const inc = @import("include");
+
+const SolutionBruteForce = struct {
+    pub fn twoSum(self: *SolutionBruteForce, nums: []i32, target: i32) [2]i32 {
+        _ = self;
+        var size: usize = nums.len;
+        var i: usize = 0;
+        // 两层循环，时间复杂度 O(n^2)
+        while (i < size - 1) : (i += 1) {
+            var j = i + 1;
+            while (j < size) : (j += 1) {
+                if (nums[i] + nums[j] == target) {
+                    return [_]i32{@intCast(i32, i), @intCast(i32, j)};
+                }
+            }
+        }
+        return undefined;
+    }
+};
+
+const SolutionHashMap = struct {
+    pub fn twoSum(self: *SolutionHashMap, nums: []i32, target: i32) ![2]i32 {
+        _ = self;
+        var size: usize = nums.len;
+        // 辅助哈希表，空间复杂度 O(n)
+        var dic = std.AutoHashMap(i32, i32).init(std.heap.page_allocator);
+        defer dic.deinit();
+        var i: usize = 0;
+        // 单层循环，时间复杂度 O(n)
+        while (i < size) : (i += 1) {
+            if (dic.contains(target - nums[i])) {
+                return [_]i32{dic.get(target - nums[i]).?, @intCast(i32, i)};
+            }
+            try dic.put(nums[i], @intCast(i32, i));
+        }
+        return undefined;
+    }
+};
+
+// Driver Code
+pub fn main() !void {
+    // ======= Test Case =======
+    var nums = [_]i32{ 2, 7, 11, 15 };
+    var target: i32 = 9;
+    // 方法一
+    var slt1 = SolutionBruteForce{};
+    var res = slt1.twoSum(&nums, target);
+    std.debug.print("方法一 res = ", .{});
+    inc.PrintUtil.printArray(i32, &res); 
+    // 方法二
+    var slt2 = SolutionHashMap{};
+    res = try slt2.twoSum(&nums, target);
+    std.debug.print("方法二 res = ", .{});
+    inc.PrintUtil.printArray(i32, &res); 
+}
+

codes/zig/chapter_computational_complexity/worst_best_time_complexity.zig

@@ -3,6 +3,7 @@
 // Author: sjinzh (sjinzh@gmail.com)
 
 const std = @import("std");
+const inc = @import("include");
 
 // 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱
 pub fn randomNumbers(comptime n: usize) [n]i32 {
@@ -26,17 +27,15 @@ pub fn findOne(nums: []i32) i32 {
 }
 
 // Driver Code
-pub fn main() !void {
+pub fn main() void {
     var i: i32 = 0;
     while (i < 10) : (i += 1) {
         const n: usize = 100;
         var nums = randomNumbers(n);
         var index = findOne(&nums);
         std.debug.print("\n数组 [ 1, 2, ..., n ] 被打乱后 = ", .{});
-        for (nums) |num, j| {
-            std.debug.print("{}{s}", .{num, if (j == nums.len-1) "" else "," });
-        }
-        std.debug.print("\n数字 1 的索引为 {}\n", .{index});
+        inc.PrintUtil.printArray(i32, &nums);
+        std.debug.print("数字 1 的索引为 {}\n", .{index});
     }
 }
 

codes/zig/include/PrintUtil.zig

@@ -0,0 +1,13 @@
+// File: TreeNode.zig
+// Created Time: 2023-01-07
+// Author: sjinzh (sjinzh@gmail.com)
+
+const std = @import("std");
+
+// Print an Array
+pub fn printArray(comptime T: type, nums: []T) void {
+    std.debug.print("[", .{});
+    for (nums) |num, j| {
+        std.debug.print("{}{s}", .{num, if (j == nums.len-1) "]\n" else ", " });
+     }
+}

codes/zig/include/include.zig

@@ -0,0 +1,5 @@
+// File: include.zig
+// Created Time: 2023-01-04
+// Author: sjinzh (sjinzh@gmail.com)
+
+pub const PrintUtil = @import("PrintUtil.zig");