Merge branch 'youngyangyang04:master' into master

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/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/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();