Merge branch 'master' of github.com:youngyangyang04/leetcode-master

problems/0019.删除链表的倒数第N个节点.md

@@ -289,6 +289,30 @@ func removeNthFromEnd(_ head: ListNode?, _ n: Int) -> ListNode? {
     return dummyHead.next
 }
 ```
+
+
+PHP:
+```php
+function removeNthFromEnd($head, $n) {
+    // 设置虚拟头节点
+    $dummyHead = new ListNode();
+    $dummyHead->next = $head;
+
+    $slow = $fast = $dummyHead;
+    while($n-- && $fast != null){
+        $fast = $fast->next;
+    }
+    // fast 再走一步，让 slow 指向删除节点的上一个节点
+    $fast = $fast->next; 
+    while ($fast != NULL) {
+        $fast = $fast->next;
+        $slow = $slow->next;
+    }
+    $slow->next = $slow->next->next;
+    return $dummyHead->next;
+    }
+```
+
 Scala:
 ```scala
 object Solution {

problems/0042.接雨水.md

@@ -744,6 +744,91 @@ var trap = function(height) {
 };
 ```
 
+### TypeScript
+
+双指针法：
+
+```typescript
+function trap(height: number[]): number {
+    const length: number = height.length;
+    let resVal: number = 0;
+    for (let i = 0; i < length; i++) {
+        let leftMaxHeight: number = height[i],
+            rightMaxHeight: number = height[i];
+        let leftIndex: number = i - 1,
+            rightIndex: number = i + 1;
+        while (leftIndex >= 0) {
+            if (height[leftIndex] > leftMaxHeight)
+                leftMaxHeight = height[leftIndex];
+            leftIndex--;
+        }
+        while (rightIndex < length) {
+            if (height[rightIndex] > rightMaxHeight)
+                rightMaxHeight = height[rightIndex];
+            rightIndex++;
+        }
+        resVal += Math.min(leftMaxHeight, rightMaxHeight) - height[i];
+    }
+    return resVal;
+};
+```
+
+动态规划：
+
+```typescript
+function trap(height: number[]): number {
+    const length: number = height.length;
+    const leftMaxHeightDp: number[] = [],
+        rightMaxHeightDp: number[] = [];
+    leftMaxHeightDp[0] = height[0];
+    rightMaxHeightDp[length - 1] = height[length - 1];
+    for (let i = 1; i < length; i++) {
+        leftMaxHeightDp[i] = Math.max(height[i], leftMaxHeightDp[i - 1]);
+    }
+    for (let i = length - 2; i >= 0; i--) {
+        rightMaxHeightDp[i] = Math.max(height[i], rightMaxHeightDp[i + 1]);
+    }
+    let resVal: number = 0;
+    for (let i = 0; i < length; i++) {
+        resVal += Math.min(leftMaxHeightDp[i], rightMaxHeightDp[i]) - height[i];
+    }
+    return resVal;
+};
+```
+
+单调栈：
+
+```typescript
+function trap(height: number[]): number {
+    const length: number = height.length;
+    const stack: number[] = [];
+    stack.push(0);
+    let resVal: number = 0;
+    for (let i = 1; i < length; i++) {
+        let top = stack[stack.length - 1];
+        if (height[top] > height[i]) {
+            stack.push(i);
+        } else if (height[top] === height[i]) {
+            stack.pop();
+            stack.push(i);
+        } else {
+            while (stack.length > 0 && height[top] < height[i]) {
+                let mid = stack.pop();
+                if (stack.length > 0) {
+                    let left = stack[stack.length - 1];
+                    let h = Math.min(height[left], height[i]) - height[mid];
+                    let w = i - left - 1;
+                    resVal += h * w;
+                    top = stack[stack.length - 1];
+                }
+            }
+            stack.push(i);
+        }
+    }
+    return resVal;
+};
+```
+
 ### C:
 
 一种更简便的双指针方法：

problems/0046.全排列.md

@@ -341,7 +341,7 @@ function permute(nums: number[]): number[][] {
     return resArr;
     function backTracking(nums: number[], route: number[]): void {
         if (route.length === nums.length) {
-            resArr.push(route.slice());
+            resArr.push([...route]);
             return;
         }
         let tempVal: number;

problems/0047.全排列II.md

@@ -268,7 +268,7 @@ var permuteUnique = function (nums) {
 
     function backtracing( used) {
         if (path.length === nums.length) {
-            result.push(path.slice())
+            result.push([...path])
             return
         }
         for (let i = 0; i < nums.length; i++) {
@@ -303,7 +303,7 @@ function permuteUnique(nums: number[]): number[][] {
     return resArr;
     function backTracking(nums: number[], route: number[]): void {
         if (route.length === nums.length) {
-            resArr.push(route.slice());
+            resArr.push([...route]);
             return;
         }
         for (let i = 0, length = nums.length; i < length; i++) {

problems/0052.N皇后II.md

@@ -44,7 +44,7 @@ n 皇后问题研究的是如何将 n 个皇后放置在 n×n 的棋盘上，并
 # 思路
 
 
-想看：[51.N皇后](https://mp.weixin.qq.com/s/lU_QwCMj6g60nh8m98GAWg) ，基本没有区别
+详看：[51.N皇后](https://mp.weixin.qq.com/s/lU_QwCMj6g60nh8m98GAWg) ，基本没有区别
 
 # C++代码
 

problems/0078.子集.md

@@ -260,7 +260,7 @@ var subsets = function(nums) {
     let result = []
     let path = []
     function backtracking(startIndex) {
-        result.push(path.slice())
+        result.push([...path])
         for(let i = startIndex; i < nums.length; i++) {
             path.push(nums[i])
             backtracking(i + 1)
@@ -280,7 +280,7 @@ function subsets(nums: number[]): number[][] {
     backTracking(nums, 0, []);
     return resArr;
     function backTracking(nums: number[], startIndex: number, route: number[]): void {
-        resArr.push(route.slice());
+        resArr.push([...route]);
         let length = nums.length;
         if (startIndex === length) return;
         for (let i = startIndex; i < length; i++) {

problems/0084.柱状图中最大的矩形.md

@@ -486,5 +486,95 @@ var largestRectangleArea = function(heights) {
     return maxArea;
 };
 ```
+TypeScript：
+
+> 双指针法（会超时）：
+
+```typescript
+function largestRectangleArea(heights: number[]): number {
+    let resMax: number = 0;
+    for (let i = 0, length = heights.length; i < length; i++) {
+        // 左开右开
+        let left: number = i - 1,
+            right: number = i + 1;
+        while (left >= 0 && heights[left] >= heights[i]) {
+            left--;
+        }
+        while (right < length && heights[right] >= heights[i]) {
+            right++;
+        }
+        resMax = Math.max(resMax, heights[i] * (right - left - 1));
+    }
+    return resMax;
+};
+```
+
+> 动态规划预处理：
+
+```typescript
+function largestRectangleArea(heights: number[]): number {
+    const length: number = heights.length;
+    const leftHeightDp: number[] = [],
+        rightHeightDp: number[] = [];
+    leftHeightDp[0] = -1;
+    rightHeightDp[length - 1] = length;
+    for (let i = 1; i < length; i++) {
+        let j = i - 1;
+        while (j >= 0 && heights[i] <= heights[j]) {
+            j = leftHeightDp[j];
+        }
+        leftHeightDp[i] = j;
+    }
+    for (let i = length - 2; i >= 0; i--) {
+        let j = i + 1;
+        while (j < length && heights[i] <= heights[j]) {
+            j = rightHeightDp[j];
+        }
+        rightHeightDp[i] = j;
+    }
+    let resMax: number = 0;
+    for (let i = 0; i < length; i++) {
+        let area = heights[i] * (rightHeightDp[i] - leftHeightDp[i] - 1);
+        resMax = Math.max(resMax, area);
+    }
+    return resMax;
+};
+```
+
+> 单调栈：
+
+```typescript
+function largestRectangleArea(heights: number[]): number {
+    heights.push(0);
+    const length: number = heights.length;
+    // 栈底->栈顶：严格单调递增
+    const stack: number[] = [];
+    stack.push(0);
+    let resMax: number = 0;
+    for (let i = 1; i < length; i++) {
+        let top = stack[stack.length - 1];
+        if (heights[top] < heights[i]) {
+            stack.push(i);
+        } else if (heights[top] === heights[i]) {
+            stack.pop();
+            stack.push(i);
+        } else {
+            while (stack.length > 0 && heights[top] > heights[i]) {
+                let mid = stack.pop();
+                let left = stack.length > 0 ? stack[stack.length - 1] : -1;
+                let w = i - left - 1;
+                let h = heights[mid];
+                resMax = Math.max(resMax, w * h);
+                top = stack[stack.length - 1];
+            }
+            stack.push(i);
+        }
+    }
+    return resMax;
+};
+```
+
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0090.子集II.md

@@ -299,7 +299,7 @@ var subsetsWithDup = function(nums) {
         return a - b
     })
     function backtracing(startIndex, sortNums) {
-        result.push(path.slice(0))
+        result.push([...path])
         if(startIndex > nums.length - 1) {
             return
         }
@@ -327,7 +327,7 @@ function subsetsWithDup(nums: number[]): number[][] {
     backTraking(nums, 0, []);
     return resArr;
     function backTraking(nums: number[], startIndex: number, route: number[]): void {
-        resArr.push(route.slice());
+        resArr.push([...route]);
         let length: number = nums.length;
         if (startIndex === length) return;
         for (let i = startIndex; i < length; i++) {

problems/0093.复原IP地址.md

@@ -444,7 +444,7 @@ var restoreIpAddresses = function(s) {
             return;
         }
         for(let j = i; j < s.length; j++) {
-            const str = s.substr(i, j - i + 1);
+            const str = s.slice(i, j + 1);
             if(str.length > 3 || +str > 255) break;
             if(str.length > 1 && str[0] === "0") break;
             path.push(str);

problems/0104.二叉树的最大深度.md

@@ -495,7 +495,7 @@ class solution:
 
 
 ## go 
-
+### 104.二叉树的最大深度
 ```go
 /**
  * definition for a binary tree node.
@@ -548,6 +548,8 @@ func maxdepth(root *treenode) int {
 
 ## javascript 
 
+### 104.二叉树的最大深度
+
 ```javascript
 var maxdepth = function(root) {
     if (root === null) return 0;
@@ -595,6 +597,8 @@ var maxDepth = function(root) {
 };
 ```
 
+### 559.n叉树的最大深度
+
 N叉树的最大深度  递归写法
 ```js
 var maxDepth = function(root) {
@@ -627,9 +631,9 @@ var maxDepth = function(root) {
 };
 ```
 
-## TypeScript：
+## TypeScript
 
-> 二叉树的最大深度：
+### 104.二叉树的最大深度
 
 ```typescript
 // 后续遍历（自下而上）
@@ -672,7 +676,7 @@ function maxDepth(root: TreeNode | null): number {
 };
 ```
 
-> N叉树的最大深度
+### 559.n叉树的最大深度
 
 ```typescript
 // 后续遍历（自下而上）
@@ -702,6 +706,8 @@ function maxDepth(root: TreeNode | null): number {
 
 ## C
 
+### 104.二叉树的最大深度
+
 二叉树最大深度递归
 ```c
 int maxDepth(struct TreeNode* root){
@@ -758,7 +764,8 @@ int maxDepth(struct TreeNode* root){
 
 ## Swift
 
->二叉树最大深度
+### 104.二叉树的最大深度
+
 ```swift
 // 递归 - 后序
 func maxDepth1(_ root: TreeNode?) -> Int {
@@ -797,7 +804,8 @@ func maxDepth(_ root: TreeNode?) -> Int {
 }
 ```
 
->N叉树最大深度
+### 559.n叉树的最大深度
+
 ```swift
 // 递归
 func maxDepth(_ root: Node?) -> Int {
@@ -833,5 +841,84 @@ func maxDepth1(_ root: Node?) -> Int {
 }
 ```
 
+## Scala
+
+### 104.二叉树的最大深度
+递归法:
+```scala
+object Solution {
+  def maxDepth(root: TreeNode): Int = {
+    def process(curNode: TreeNode): Int = {
+      if (curNode == null) return 0
+      // 递归左节点和右节点，返回最大的，最后+1
+      math.max(process(curNode.left), process(curNode.right)) + 1
+    }
+    // 调用递归方法，return关键字可以省略
+    process(root) 
+  }
+}
+```
+
+迭代法:
+```scala
+object Solution {
+  import scala.collection.mutable
+  def maxDepth(root: TreeNode): Int = {
+    var depth = 0
+    if (root == null) return depth
+    val queue = mutable.Queue[TreeNode]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      val len = queue.size
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+      depth += 1  // 只要有层次就+=1
+    }
+    depth
+  }
+}
+```
+
+### 559.n叉树的最大深度
+
+递归法:
+```scala
+object Solution {
+  def maxDepth(root: Node): Int = {
+    if (root == null) return 0
+    var depth = 0
+    for (node <- root.children) {
+      depth = math.max(depth, maxDepth(node))
+    }
+    depth + 1
+  }
+}
+```
+
+迭代法: (层序遍历)
+```scala
+object Solution {
+  import scala.collection.mutable
+  def maxDepth(root: Node): Int = {
+    if (root == null) return 0
+    var depth = 0
+    val queue = mutable.Queue[Node]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      val len = queue.size
+      depth += 1
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        for (node <- curNode.children) queue.enqueue(node)
+      }
+    }
+    depth
+  }
+}
+```
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0106.从中序与后序遍历序列构造二叉树.md

@@ -1091,7 +1091,53 @@ class Solution_0106 {
 }
 ```
 
+## Scala
 
+106 从中序与后序遍历序列构造二叉树
+
+```scala
+object Solution {
+  def buildTree(inorder: Array[Int], postorder: Array[Int]): TreeNode = {
+    // 1、如果长度为0，则直接返回null
+    var len = inorder.size
+    if (len == 0) return null
+    // 2、后序数组的最后一个元素是当前根元素
+    var rootValue = postorder(len - 1)
+    var root: TreeNode = new TreeNode(rootValue, null, null)
+    if (len == 1) return root   // 如果数组只有一个节点，就直接返回
+    // 3、在中序数组中找到切割点的索引
+    var delimiterIndex: Int = inorder.indexOf(rootValue)
+    // 4、切分数组往下迭代
+    root.left = buildTree(inorder.slice(0, delimiterIndex), postorder.slice(0, delimiterIndex))
+    root.right = buildTree(inorder.slice(delimiterIndex + 1, len), postorder.slice(delimiterIndex, len - 1))
+    root   // 返回root，return关键字可以省略
+  }
+}
+```
+
+105 从前序与中序遍历序列构造二叉树
+
+```scala
+object Solution {
+  def buildTree(preorder: Array[Int], inorder: Array[Int]): TreeNode = {
+    // 1、如果长度为0，直接返回空
+    var len = inorder.size
+    if (len == 0) return null
+    // 2、前序数组的第一个元素是当前子树根节点
+    var rootValue = preorder(0)
+    var root = new TreeNode(rootValue, null, null)
+    if (len == 1) return root // 如果数组元素只有一个，那么返回根节点
+    // 3、在中序数组中，找到切割点
+    var delimiterIndex = inorder.indexOf(rootValue)
+
+    // 4、切分数组往下迭代
+    root.left = buildTree(preorder.slice(1, delimiterIndex + 1), inorder.slice(0, delimiterIndex))
+    root.right = buildTree(preorder.slice(delimiterIndex + 1, preorder.size), inorder.slice(delimiterIndex + 1, len))
+
+    root
+  }
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0111.二叉树的最小深度.md

@@ -488,6 +488,46 @@ func minDepth(_ root: TreeNode?) -> Int {
 }
 ```
 
+
+## Scala
+
+递归法:
+```scala
+object Solution {
+  def minDepth(root: TreeNode): Int = {
+    if (root == null) return 0
+    if (root.left == null && root.right != null) return 1 + minDepth(root.right)
+    if (root.left != null && root.right == null) return 1 + minDepth(root.left)
+    // 如果两侧都不为空，则取最小值，return关键字可以省略
+    1 + math.min(minDepth(root.left), minDepth(root.right))
+  }
+}
+```
+
+迭代法:
+```scala
+object Solution {
+  import scala.collection.mutable
+  def minDepth(root: TreeNode): Int = {
+    if (root == null) return 0
+    var depth = 0
+    val queue = mutable.Queue[TreeNode]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      depth += 1
+      val len = queue.size
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+        if (curNode.left == null && curNode.right == null) return depth
+      }
+    }
+    depth
+  }
+}
+```
+
 rust:
 ```rust
 impl Solution {
@@ -550,6 +590,7 @@ impl Solution {
         }
         min_depth
     }
+
 ```
 
 -----------------------

problems/0112.路径总和.md

@@ -300,7 +300,7 @@ public:
 
 ## java
 
-lc112
+### 0112.路径总和
 ```java
 class solution {
    public boolean haspathsum(treenode root, int targetsum) {
@@ -373,7 +373,7 @@ class solution {
 
 ```
 
-0113.路径总和-ii
+### 0113.路径总和-ii
 
 ```java
 class solution {
@@ -436,7 +436,7 @@ class Solution {
 
 ## python
 
-0112.路径总和
+### 0112.路径总和
 
 **递归**
 ```python
@@ -488,7 +488,7 @@ class solution:
         return false
 ```
 
-0113.路径总和-ii 
+### 0113.路径总和-ii 
 
 **递归**
 ```python
@@ -545,7 +545,7 @@ class Solution:
 
 ## go
 
-112. 路径总和
+### 112. 路径总和
 
 ```go
 //递归法
@@ -570,7 +570,7 @@ func hasPathSum(root *TreeNode, targetSum int) bool {
 }
 ```
 
-113. 路径总和 II
+### 113. 路径总和 II
 
 ```go
 /**
@@ -612,7 +612,7 @@ func traverse(node *TreeNode, result *[][]int, currPath *[]int, targetSum int) {
 
 ## javascript
 
-0112.路径总和
+### 0112.路径总和
 
 **递归**
 ```javascript
@@ -673,7 +673,7 @@ let hasPathSum = function(root, targetSum) {
 };
 ```
 
-0113.路径总和-ii 
+### 0113.路径总和-ii 
 
 **递归**
 ```javascript
@@ -768,7 +768,7 @@ let pathSum = function(root, targetSum) {
 
 ## TypeScript
 
-> 0112.路径总和
+### 0112.路径总和
 
 **递归法：**
 
@@ -850,7 +850,7 @@ function hasPathSum(root: TreeNode | null, targetSum: number): boolean {
 };
 ```
 
-> 0112.路径总和 ii
+### 0112.路径总和 ii
 
 **递归法：**
 
@@ -888,7 +888,7 @@ function pathSum(root: TreeNode | null, targetSum: number): number[][] {
 
 ## Swift
 
-0112.路径总和
+### 0112.路径总和
 
 **递归**
 
@@ -955,7 +955,7 @@ func hasPathSum(_ root: TreeNode?, _ targetSum: Int) -> Bool {
 }
 ```
 
-0113.路径总和 II
+### 0113.路径总和 II
 
 **递归**
 
@@ -1126,7 +1126,90 @@ int** pathSum(struct TreeNode* root, int targetSum, int* returnSize, int** retur
 }
 ```
 
+## Scala
 
+### 0112.路径总和
+
+**递归:**
+```scala
+object Solution {
+  def hasPathSum(root: TreeNode, targetSum: Int): Boolean = {
+    if(root == null) return false
+    var res = false
+
+    def traversal(curNode: TreeNode, sum: Int): Unit = {
+      if (res) return // 如果直接标记为true了，就没有往下递归的必要了
+      if (curNode.left == null && curNode.right == null && sum == targetSum) {
+        res = true
+        return
+      }
+      // 往下递归
+      if (curNode.left != null) traversal(curNode.left, sum + curNode.left.value)
+      if (curNode.right != null) traversal(curNode.right, sum + curNode.right.value)
+    }
+
+    traversal(root, root.value)
+    res // return关键字可以省略
+  }
+}
+```
+
+**迭代:**
+```scala
+object Solution {
+  import scala.collection.mutable
+  def hasPathSum(root: TreeNode, targetSum: Int): Boolean = {
+    if (root == null) return false
+    val stack = mutable.Stack[(TreeNode, Int)]()
+    stack.push((root, root.value)) // 将根节点元素放入stack
+    while (!stack.isEmpty) {
+      val curNode = stack.pop() // 取出栈顶元素
+      // 如果遇到叶子节点，看当前的值是否等于targetSum，等于则返回true
+      if (curNode._1.left == null && curNode._1.right == null && curNode._2 == targetSum) {
+        return true
+      }
+      if (curNode._1.right != null) stack.push((curNode._1.right, curNode._2 + curNode._1.right.value))
+      if (curNode._1.left != null) stack.push((curNode._1.left, curNode._2 + curNode._1.left.value))
+    }
+    false //如果没有返回true，即可返回false，return关键字可以省略
+  }
+}
+```
+
+### 0113.路径总和 II
+
+**递归:**
+```scala
+object Solution {
+  import scala.collection.mutable.ListBuffer
+  def pathSum(root: TreeNode, targetSum: Int): List[List[Int]] = {
+    val res = ListBuffer[List[Int]]()
+    if (root == null) return res.toList
+    val path = ListBuffer[Int]();
+
+    def traversal(cur: TreeNode, count: Int): Unit = {
+      if (cur.left == null && cur.right == null && count == 0) {
+        res.append(path.toList)
+        return
+      }
+      if (cur.left != null) {
+        path.append(cur.left.value)
+        traversal(cur.left, count - cur.left.value)
+        path.remove(path.size - 1)
+      }
+      if (cur.right != null) {
+        path.append(cur.right.value)
+        traversal(cur.right, count - cur.right.value)
+        path.remove(path.size - 1)
+      }
+    }
+
+    path.append(root.value)
+    traversal(root, targetSum - root.value)
+    res.toList
+  }
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0131.分割回文串.md

@@ -442,7 +442,7 @@ var partition = function(s) {
         }
         for(let j = i; j < len; j++) {
             if(!isPalindrome(s, i, j)) continue;
-            path.push(s.substr(i, j - i + 1));
+            path.push(s.slice(i, j + 1));
             backtracking(j + 1);
             path.pop();
         }

problems/0151.翻转字符串里的单词.md

@@ -817,6 +817,53 @@ object Solution {
 ```
 
 
+PHP:
+```php
+function reverseWords($s) {
+    $this->removeExtraSpaces($s); 
+    $this->reverseString($s, 0, strlen($s)-1);
+    // 将每个单词反转
+    $start = 0; 
+    for ($i = 0; $i <= strlen($s); $i++) {
+        // 到达空格或者串尾，说明一个单词结束。进行翻转。
+        if ($i == strlen($s) || $s[$i] == ' ') { 
+            // 翻转，注意是左闭右闭 []的翻转。
+            $this->reverseString($s, $start, $i-1);
+            // +1: 单词与单词直接有个空格
+            $start = $i + 1; 
+        }
+    }
+    return $s;
+}
+
+// 移除多余空格
+function removeExtraSpaces(&$s){
+    $slow = 0;   
+    for ($i = 0; $i < strlen($s); $i++) {
+        if ($s[$i] != ' ') { 
+            if ($slow != 0){
+                $s[$slow++] = ' ';
+            } 
+            while ($i < strlen($s) && $s[$i] != ' ') { 
+                $s[$slow++] = $s[$i++];
+            }
+        }
+    }
+    // 移动覆盖处理，丢弃多余的脏数据。
+    $s = substr($s,0,$slow);
+    return ;
+}
+
+// 翻转字符串
+function reverseString(&$s, $start, $end) {
+    for ($i = $start, $j = $end; $i < $j; $i++, $j--) {
+        $tmp = $s[$i];
+        $s[$i] = $s[$j];
+        $s[$j] = $tmp;
+    }
+    return ;
+}
+```
 
 
 -----------------------

problems/0206.翻转链表.md

@@ -496,8 +496,26 @@ struct ListNode* reverseList(struct ListNode* head){
     return reverse(NULL, head);
 }
 ```
-Scala:
 
+
+
+PHP:
+```php
+// 双指针法：
+function reverseList($head) {
+    $cur = $head;
+    $pre = NULL;
+    while($cur){
+        $temp = $cur->next; 
+        $cur->next = $pre;
+        $pre = $cur;
+        $cur = $temp;
+    }
+    return $pre;
+    }
+```
+
+Scala:
 双指针法：
 ```scala
 object Solution {
@@ -529,6 +547,7 @@ object Solution {
     cur.next = pre
     reverse(cur, tmp)   // 此时cur成为前一个节点，tmp是当前节点
   }
+
 }
 ```
 -----------------------

problems/0216.组合总和III.md

@@ -360,39 +360,30 @@ func backTree(n,k,startIndex int,track *[]int,result *[][]int){
 ## javaScript
 
 ```js
-// 等差数列
+/**
-var maxV = k => k * (9 + 10 - k) / 2;
+ * @param {number} k
-var minV = k => k * (1 + k) / 2;
+ * @param {number} n
+ * @return {number[][]}
+ */
 var combinationSum3 = function(k, n) {
-    if (k > 9 || k < 1) return [];
+    const backtrack = (start) => {
-    // if (n > maxV(k) || n < minV(k)) return [];
+        const l = path.length;
-    // if (n === maxV(k)) return [Array.from({length: k}).map((v, i) => 9 - i)];
+        if (l === k) {
-    // if (n === minV(k)) return [Array.from({length: k}).map((v, i) => i + 1)];
+            const sum = path.reduce((a, b) => a + b);
-
+            if (sum === n) {
-    const res = [], path = [];
+                res.push([...path]);
-    backtracking(k, n, 1, 0);
+            }
-    return res;
-    function backtracking(k, n, i, sum){
-        const len = path.length;
-        if (len > k || sum > n) return;
-        if (maxV(k - len) < n - sum) return;
-        if (minV(k - len) > n - sum) return; 
-
-        if(len === k && sum == n) {
-            res.push(Array.from(path));
             return;
         }
-
+        for (let i = start; i <= 9 - (k - l) + 1; i++) {
-        const min = Math.min(n - sum, 9 + len - k + 1);
+            path.push(i);
-
+            backtrack(i + 1);
-        for(let a = i; a <= min; a++) {
-            path.push(a);
-            sum += a;
-            backtracking(k, n, a + 1, sum);
             path.pop();
-            sum -= a;
         }
     }
+    let res = [], path = [];
+    backtrack(1);
+    return res;
 };
 ```
 

problems/0222.完全二叉树的节点个数.md

@@ -646,5 +646,68 @@ func countNodes(_ root: TreeNode?) -> Int {
 }
 ```
 
+## Scala
+
+递归:
+```scala
+object Solution {
+  def countNodes(root: TreeNode): Int = {
+    if(root == null) return 0
+    1 + countNodes(root.left) + countNodes(root.right)
+  }
+}
+```
+
+层序遍历:
+```scala
+object Solution {
+  import scala.collection.mutable
+  def countNodes(root: TreeNode): Int = {
+    if (root == null) return 0
+    val queue = mutable.Queue[TreeNode]()
+    var node = 0
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      val len = queue.size
+      for (i <- 0 until len) {
+        node += 1
+        val curNode = queue.dequeue()
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+    }
+    node
+  }
+}
+```
+
+利用完全二叉树性质:
+```scala
+object Solution {
+  def countNodes(root: TreeNode): Int = {
+    if (root == null) return 0
+    var leftNode = root.left
+    var rightNode = root.right
+    // 向左向右往下探
+    var leftDepth = 0
+    while (leftNode != null) {
+      leftDepth += 1
+      leftNode = leftNode.left
+    }
+    var rightDepth = 0
+    while (rightNode != null) {
+      rightDepth += 1
+      rightNode = rightNode.right
+    }
+    // 如果相等就是一个满二叉树
+    if (leftDepth == rightDepth) {
+      return (2 << leftDepth) - 1
+    }
+    // 如果不相等就不是一个完全二叉树，继续向下递归
+    countNodes(root.left) + countNodes(root.right) + 1
+  }
+}
+```
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0257.二叉树的所有路径.md

@@ -702,5 +702,35 @@ func binaryTreePaths(_ root: TreeNode?) -> [String] {
 }
 ```
 
+Scala:
+
+递归:
+```scala
+object Solution {
+  import scala.collection.mutable.ListBuffer
+  def binaryTreePaths(root: TreeNode): List[String] = {
+    val res = ListBuffer[String]()
+    def traversal(curNode: TreeNode, path: ListBuffer[Int]): Unit = {
+      path.append(curNode.value)
+      if (curNode.left == null && curNode.right == null) {
+        res.append(path.mkString("->")) // mkString函数: 将数组的所有值按照指定字符串拼接
+        return // 处理完可以直接return
+      }
+
+      if (curNode.left != null) {
+        traversal(curNode.left, path)
+        path.remove(path.size - 1)
+      }
+      if (curNode.right != null) {
+        traversal(curNode.right, path)
+        path.remove(path.size - 1)
+      }
+    }
+    traversal(root, ListBuffer[Int]())
+    res.toList
+  }
+}
+```
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0344.反转字符串.md

@@ -266,6 +266,38 @@ public class Solution
     }
 }
 ```
+
+
+PHP：
+```php
+// 双指针
+// 一：
+function reverseString(&$s) {
+    $left = 0;
+    $right = count($s)-1;
+    while($left<$right){
+        $temp = $s[$left];
+        $s[$left] = $s[$right];
+        $s[$right] = $temp;
+        $left++;
+        $right--;
+    }
+}
+
+// 二：
+function reverseString(&$s) {
+    $this->reverse($s,0,count($s)-1);
+}
+// 按指定位置交换元素
+function reverse(&$s, $start, $end) {
+    for ($i = $start, $j = $end; $i < $j; $i++, $j--) {
+        $tmp = $s[$i];
+        $s[$i] = $s[$j];
+        $s[$j] = $tmp;
+    }
+    }
+```
+
 Scala:
 ```scala
 object Solution {

problems/0404.左叶子之和.md

@@ -516,6 +516,44 @@ int sumOfLeftLeaves(struct TreeNode* root){
 }
 ```
 
+## Scala
+
+**递归:**
+```scala
+object Solution {
+  def sumOfLeftLeaves(root: TreeNode): Int = {
+    if(root == null) return 0
+    var midValue = 0
+    if(root.left != null && root.left.left == null && root.left.right == null){
+      midValue = root.left.value
+    }
+    // return关键字可以省略
+    midValue + sumOfLeftLeaves(root.left) + sumOfLeftLeaves(root.right)
+  }
+}
+```
+
+**迭代:**
+```scala
+object Solution {
+  import scala.collection.mutable
+  def sumOfLeftLeaves(root: TreeNode): Int = {
+    val stack = mutable.Stack[TreeNode]()
+    if (root == null) return 0
+    stack.push(root)
+    var sum = 0
+    while (!stack.isEmpty) {
+      val curNode = stack.pop()
+      if (curNode.left != null && curNode.left.left == null && curNode.left.right == null) {
+        sum += curNode.left.value // 如果满足条件就累加
+      }
+      if (curNode.right != null) stack.push(curNode.right)
+      if (curNode.left != null) stack.push(curNode.left)
+    }
+    sum
+  }
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0416.分割等和子集.md

@@ -417,6 +417,26 @@ var canPartition = function(nums) {
 ```
 
 
+TypeScript:
+
+```ts
+function canPartition(nums: number[]): boolean {
+    const sum: number = nums.reduce((a: number, b: number): number => a + b);
+    if (sum % 2 === 1) return false;
+    const target: number = sum / 2;
+    // dp[j]表示容量（总数和）为j的背包所能装下的数（下标[0, i]之间任意取）的总和（<= 容量）的最大值
+    const dp: number[] = new Array(target + 1).fill(0);
+    const n: number = nums.length;
+    for (let i: number = 0; i < n; i++) {
+        for (let j: number = target; j >= nums[i]; j--) {
+            dp[j] = Math.max(dp[j], dp[j - nums[i]] + nums[i]);
+        }
+    }
+    return dp[target] === target;
+};
+```
+
+
 C:
 二维dp：
 ```c
@@ -575,6 +595,5 @@ function canPartition(nums: number[]): boolean {
 
 
 
-
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0494.目标和.md

@@ -351,22 +351,26 @@ const findTargetSumWays = (nums, target) => {
 };
 ```
 
-TypeScript：
 
-```typescript
+TypeScript:
+
+```ts
 function findTargetSumWays(nums: number[], target: number): number {
-    const sum: number = nums.reduce((pre, cur) => pre + cur);
+    // 把数组分成两个组合left, right.left + right = sum, left - right = target.
-    if (Math.abs(target) > sum) return 0;
+    const sum: number = nums.reduce((a: number, b: number): number => a + b);
-    if ((target + sum) % 2 === 1) return 0;
+    if ((sum + target) % 2 || Math.abs(target) > sum)  return 0;
-    const bagSize: number = (target + sum) / 2;
+    const left: number = (sum + target) / 2;
-    const dp: number[] = new Array(bagSize + 1).fill(0);
+    
-    dp[0] = 1;
+    // 将问题转化为装满容量为left的背包有多少种方法
-    for (let i = 0; i < nums.length; i++) {
+    // dp[i]表示装满容量为i的背包有多少种方法
-        for (let j = bagSize; j >= nums[i]; j--) {
+    const dp: number[] = new Array(left + 1).fill(0);
+    dp[0] = 1;  // 装满容量为0的背包有1种方法（什么也不装）
+    for (let i: number = 0; i < nums.length; i++) {
+        for (let j: number = left; j >= nums[i]; j--) {
             dp[j] += dp[j - nums[i]];
         }
     }
-    return dp[bagSize];
+    return dp[left];
 };
 ```
 

problems/0496.下一个更大元素I.md

@@ -332,5 +332,36 @@ var nextGreaterElement = function (nums1, nums2) {
 };
 ```
 
+TypeScript：
+
+```typescript
+function nextGreaterElement(nums1: number[], nums2: number[]): number[] {
+    const resArr: number[] = new Array(nums1.length).fill(-1);
+    const stack: number[] = [];
+    const helperMap: Map<number, number> = new Map();
+    nums1.forEach((num, index) => {
+        helperMap.set(num, index);
+    })
+    stack.push(0);
+    for (let i = 1, length = nums2.length; i < length; i++) {
+        let top = stack[stack.length - 1];
+        while (stack.length > 0 && nums2[top] < nums2[i]) {
+            let index = helperMap.get(nums2[top]);
+            if (index !== undefined) {
+                resArr[index] = nums2[i];
+            }
+            stack.pop();
+            top = stack[stack.length - 1];
+        }
+        if (helperMap.get(nums2[i]) !== undefined) {
+            stack.push(i);
+        }
+    }
+    return resArr;
+};
+```
+
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0503.下一个更大元素II.md

@@ -182,5 +182,31 @@ var nextGreaterElements = function (nums) {
   return res;
 };
 ```
+TypeScript：
+
+```typescript
+function nextGreaterElements(nums: number[]): number[] {
+    const length: number = nums.length;
+    const stack: number[] = [];
+    stack.push(0);
+    const resArr: number[] = new Array(length).fill(-1);
+    for (let i = 1; i < length * 2; i++) {
+        const index = i % length;
+        let top = stack[stack.length - 1];
+        while (stack.length > 0 && nums[top] < nums[index]) {
+            resArr[top] = nums[index];
+            stack.pop();
+            top = stack[stack.length - 1];
+        }
+        if (i < length) {
+            stack.push(i);
+        }
+    }
+    return resArr;
+};
+```
+
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0513.找树左下角的值.md

@@ -546,7 +546,50 @@ func findBottomLeftValue(_ root: TreeNode?) -> Int {
 }
 ```
 
+## Scala
 
+递归版本:
+```scala
+object Solution {
+  def findBottomLeftValue(root: TreeNode): Int = {
+    var maxLeftValue = 0
+    var maxLen = Int.MinValue
+    // 递归方法
+    def traversal(node: TreeNode, leftLen: Int): Unit = {
+      // 如果左右都为空并且当前深度大于最大深度，记录最左节点的值
+      if (node.left == null && node.right == null && leftLen > maxLen) {
+        maxLen = leftLen
+        maxLeftValue = node.value
+      }
+      if (node.left != null) traversal(node.left, leftLen + 1)
+      if (node.right != null) traversal(node.right, leftLen + 1)
+    }
+    traversal(root, 0)  // 调用方法
+    maxLeftValue    // return关键字可以省略
+  }
+}
+```
+
+层序遍历:
+```scala
+  import scala.collection.mutable
+
+  def findBottomLeftValue(root: TreeNode): Int = {
+    val queue = mutable.Queue[TreeNode]()
+    queue.enqueue(root)
+    var res = 0   // 记录每层最左侧结果
+    while (!queue.isEmpty) {
+      val len = queue.size
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        if (i == 0) res = curNode.value // 记录最最左侧的节点
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+    }
+    res // 最终返回结果，return关键字可以省略
+  }
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0516.最长回文子序列.md

@@ -235,6 +235,35 @@ const longestPalindromeSubseq = (s) => {
 };
 ```
 
+TypeScript：
+
+```typescript
+function longestPalindromeSubseq(s: string): number {
+    /**
+        dp[i][j]：[i,j]区间内，最长回文子序列的长度 
+     */
+    const length: number = s.length;
+    const dp: number[][] = new Array(length).fill(0)
+        .map(_ => new Array(length).fill(0));
+    for (let i = 0; i < length; i++) {
+        dp[i][i] = 1;
+    }
+    // 自下而上，自左往右遍历
+    for (let i = length - 1; i >= 0; i--) {
+        for (let j = i + 1; j < length; j++) {
+            if (s[i] === s[j]) {
+                dp[i][j] = dp[i + 1][j - 1] + 2;
+            } else {
+                dp[i][j] = Math.max(dp[i][j - 1], dp[i + 1][j]);
+            }
+        }
+    }
+    return dp[0][length - 1];
+};
+```
+
+
+
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0647.回文子串.md

@@ -406,6 +406,63 @@ const countSubstrings = (s) => {
 }
 ```
 
+TypeScript：
+
+> 动态规划：
+
+```typescript
+function countSubstrings(s: string): number {
+    /**
+        dp[i][j]: [i,j]区间内的字符串是否为回文(左闭右闭)
+     */
+    const length: number = s.length;
+    const dp: boolean[][] = new Array(length).fill(0)
+        .map(_ => new Array(length).fill(false));
+    let resCount: number = 0;
+    // 自下而上，自左向右遍历
+    for (let i = length - 1; i >= 0; i--) {
+        for (let j = i; j < length; j++) {
+            if (
+                s[i] === s[j] &&
+                (j - i <= 1 || dp[i + 1][j - 1] === true)
+            ) {
+                dp[i][j] = true;
+                resCount++;
+            }
+        }
+    }
+    return resCount;
+};
+```
+
+> 双指针法：
+
+```typescript
+function countSubstrings(s: string): number {
+    const length: number = s.length;
+    let resCount: number = 0;
+    for (let i = 0; i < length; i++) {
+        resCount += expandRange(s, i, i);
+        resCount += expandRange(s, i, i + 1);
+    }
+    return resCount;
+};
+function expandRange(s: string, left: number, right: number): number {
+    let palindromeNum: number = 0;
+    while (
+        left >= 0 && right < s.length &&
+        s[left] === s[right]
+    ) {
+        palindromeNum++;
+        left--;
+        right++;
+    }
+    return palindromeNum;
+}
+```
+
+
+
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/0739.每日温度.md

@@ -372,6 +372,32 @@ var dailyTemperatures = function(temperatures) {
 };
 ```
 
+TypeScript:
+
+> 精简版：
+
+```typescript
+function dailyTemperatures(temperatures: number[]): number[] {
+    const length: number = temperatures.length;
+    const stack: number[] = [];
+    const resArr: number[] = new Array(length).fill(0);
+    stack.push(0);
+    for (let i = 1; i < length; i++) {
+        let top = stack[stack.length - 1];
+        while (
+            stack.length > 0 &&
+            temperatures[top] < temperatures[i]
+        ) {
+            resArr[top] = i - top;
+            stack.pop();
+            top = stack[stack.length - 1];
+        }
+        stack.push(i);
+    }
+    return resArr;
+};
+```
+
 
 
 

problems/0941.有效的山脉数组.md

@@ -157,6 +157,26 @@ var validMountainArray = function(arr) {
 };
 ```
 
+## TypeScript
+
+```typescript
+function validMountainArray(arr: number[]): boolean {
+    const length: number = arr.length;
+    if (length < 3) return false;
+    let left: number = 0,
+        right: number = length - 1;
+    while (left < (length - 1) && arr[left] < arr[left + 1]) {
+        left++;
+    }
+    while (right > 0 && arr[right] < arr[right - 1]) {
+        right--;
+    }
+    if (left === right && left !== 0 && right !== length - 1)
+        return true;
+    return false;
+};
+```
+
 
 
 

problems/1049.最后一块石头的重量II.md

@@ -277,26 +277,29 @@ var lastStoneWeightII = function (stones) {
 };
 ```
 
-TypeScript：
 
-```typescript
+TypeScript版本
+
+```ts
 function lastStoneWeightII(stones: number[]): number {
-    const sum: number = stones.reduce((pre, cur) => pre + cur);
+    const sum: number = stones.reduce((a: number, b:number): number => a + b);
-    const bagSize: number = Math.floor(sum / 2);
+    const target: number = Math.floor(sum / 2);
-    const weightArr: number[] = stones;
+    const n: number = stones.length;
-    const valueArr: number[] = stones;
+    // dp[j]表示容量（总数和）为j的背包所能装下的数（下标[0, i]之间任意取）的总和（<= 容量）的最大值
-    const goodsNum: number = weightArr.length;
+    const dp: number[] = new Array(target + 1).fill(0);
-    const dp: number[] = new Array(bagSize + 1).fill(0);
+    for (let i: number = 0; i < n; i++ ) {
-    for (let i = 0; i < goodsNum; i++) {
+        for (let j: number = target; j >= stones[i]; j--) {
-        for (let j = bagSize; j >= weightArr[i]; j--) {
+            dp[j] = Math.max(dp[j], dp[j - stones[i]] + stones[i]);
-            dp[j] = Math.max(dp[j], dp[j - weightArr[i]] + valueArr[i]);
         }
     }
-    return sum - dp[bagSize] * 2;
+    return sum - dp[target] - dp[target];
 };
 ```
 
 
 
+
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/1207.独一无二的出现次数.md

@@ -150,5 +150,39 @@ var uniqueOccurrences = function(arr) {
 };
 ```
 
+TypeScript：
+
+> 借用数组：
+
+```typescript
+function uniqueOccurrences(arr: number[]): boolean {
+    const countArr: number[] = new Array(2001).fill(0);
+    for (let i = 0, length = arr.length; i < length; i++) {
+        countArr[arr[i] + 1000]++;
+    }
+    const flagArr: boolean[] = new Array(1001).fill(false);
+    for (let count of countArr) {
+        if (count === 0) continue;
+        if (flagArr[count] === true) return false;
+        flagArr[count] = true;
+    }
+    return true;
+};
+```
+
+> 借用map、set
+
+```typescript
+function uniqueOccurrences(arr: number[]): boolean {
+    const countMap: Map<number, number> = new Map();
+    arr.forEach(val => {
+        countMap.set(val, (countMap.get(val) || 0) + 1);
+    })
+    return countMap.size === new Set(countMap.values()).size;
+};
+```
+
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/1365.有多少小于当前数字的数字.md

@@ -217,6 +217,46 @@ var smallerNumbersThanCurrent = function(nums) {
 };
 ```
 
+TypeScript:
+
+> 暴力法：
+
+```typescript
+function smallerNumbersThanCurrent(nums: number[]): number[] {
+    const length: number = nums.length;
+    const resArr: number[] = [];
+    for (let i = 0; i < length; i++) {
+        let count: number = 0;
+        for (let j = 0; j < length; j++) {
+            if (nums[j] < nums[i]) {
+                count++;
+            }
+        }
+        resArr[i] = count;
+    }
+    return resArr;
+};
+```
+
+> 排序+hash
+
+```typescript
+function smallerNumbersThanCurrent(nums: number[]): number[] {
+    const length: number = nums.length;
+    const sortedArr: number[] = [...nums];
+    sortedArr.sort((a, b) => a - b);
+    const hashMap: Map<number, number> = new Map();
+    for (let i = length - 1; i >= 0; i--) {
+        hashMap.set(sortedArr[i], i);
+    }
+    const resArr: number[] = [];
+    for (let i = 0; i < length; i++) {
+        resArr[i] = hashMap.get(nums[i]);
+    }
+    return resArr;
+};
+```
+
 
 
 -----------------------

problems/剑指Offer05.替换空格.md

@@ -471,5 +471,41 @@ object Solution {
 ```
 
 
+PHP：
+```php
+function replaceSpace($s){
+    $sLen = strlen($s);
+    $moreLen = $this->spaceLen($s) * 2;
+
+    $head = $sLen - 1;
+    $tail = $sLen + $moreLen - 1;
+
+    $s = $s . str_repeat(' ', $moreLen);
+    while ($head != $tail) {
+        if ($s[$head] == ' ') {
+            $s[$tail--] = '0';
+            $s[$tail--] = '2';
+            $s[$tail] = '%';
+        } else {
+            $s[$tail] = $s[$head];
+        }
+        $head--;
+        $tail--;
+    }
+    return $s;
+}
+// 统计空格个数
+function spaceLen($s){
+    $count = 0;
+    for ($i = 0; $i < strlen($s); $i++) {
+        if ($s[$i] == ' ') {
+            $count++;
+        }
+    }
+    return $count;
+}
+```
+
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

problems/回溯算法去重问题的另一种写法.md

@@ -365,6 +365,84 @@ class Solution:
         return res
 ```
 
+JavaScript：
+
+**90.子集II**
+
+```javascript
+function subsetsWithDup(nums) {
+    nums.sort((a, b) => a - b);
+    const resArr = [];
+    backTraking(nums, 0, []);
+    return resArr;
+    function backTraking(nums, startIndex, route) {
+        resArr.push([...route]);
+        const helperSet = new Set();
+        for (let i = startIndex, length = nums.length; i < length; i++) {
+            if (helperSet.has(nums[i])) continue;
+            helperSet.add(nums[i]);
+            route.push(nums[i]);
+            backTraking(nums, i + 1, route);
+            route.pop();
+        }
+    }
+};
+```
+
+**40. 组合总和 II**
+
+```javascript
+function combinationSum2(candidates, target) {
+    candidates.sort((a, b) => a - b);
+    const resArr = [];
+    backTracking(candidates, target, 0, 0, []);
+    return resArr;
+    function backTracking( candidates, target, curSum, startIndex, route ) {
+        if (curSum > target) return;
+        if (curSum === target) {
+            resArr.push([...route]);
+            return;
+        }
+        const helperSet = new Set();
+        for (let i = startIndex, length = candidates.length; i < length; i++) {
+            let tempVal = candidates[i];
+            if (helperSet.has(tempVal)) continue;
+            helperSet.add(tempVal);
+            route.push(tempVal);
+            backTracking(candidates, target, curSum + tempVal, i + 1, route);
+            route.pop();
+        }
+    }
+};
+```
+
+**47. 全排列 II**
+
+```javaescript
+function permuteUnique(nums) {
+    const resArr = [];
+    const usedArr = [];
+    backTracking(nums, []);
+    return resArr;
+    function backTracking(nums, route) {
+        if (nums.length === route.length) {
+            resArr.push([...route]);
+            return;
+        }
+        const usedSet = new Set();
+        for (let i = 0, length = nums.length; i < length; i++) {
+            if (usedArr[i] === true || usedSet.has(nums[i])) continue;
+            usedSet.add(nums[i]);
+            route.push(nums[i]);
+            usedArr[i] = true;
+            backTracking(nums, route);
+            usedArr[i] = false;
+            route.pop();
+        }
+    }
+};
+```
+
 TypeScript：
 
 **90.子集II**
@@ -376,7 +454,7 @@ function subsetsWithDup(nums: number[]): number[][] {
     backTraking(nums, 0, []);
     return resArr;
     function backTraking(nums: number[], startIndex: number, route: number[]): void {
-        resArr.push(route.slice());
+        resArr.push([...route]);
         const helperSet: Set<number> = new Set();
         for (let i = startIndex, length = nums.length; i < length; i++) {
             if (helperSet.has(nums[i])) continue;
@@ -403,7 +481,7 @@ function combinationSum2(candidates: number[], target: number): number[][] {
     ) {
         if (curSum > target) return;
         if (curSum === target) {
-            resArr.push(route.slice());
+            resArr.push([...route]);
             return;
         }
         const helperSet: Set<number> = new Set();
@@ -430,7 +508,7 @@ function permuteUnique(nums: number[]): number[][] {
     return resArr;
     function backTracking(nums: number[], route: number[]): void {
         if (nums.length === route.length) {
-            resArr.push(route.slice());
+            resArr.push([...route]);
             return;
         }
         const usedSet: Set<number> = new Set();