Merge pull request youngyangyang04#1256 from pzppzz/master

更新了0015三数之和javascript版本，去除多余代码

Author: youngyangyang04

problems/0015.三数之和.md

@@ -313,54 +313,36 @@ func threeSum(nums []int)[][]int{
 javaScript: 
 
 ```js
-/**
- * @param {number[]} nums
- * @return {number[][]}
- */
-
-// 循环内不考虑去重 
-var threeSum = function(nums) {
-    const len = nums.length;
-    if(len < 3) return [];
-    nums.sort((a, b) => a - b);
-    const resSet = new Set();
-    for(let i = 0; i < len - 2; i++) {
-        if(nums[i] > 0) break;
-        let l = i + 1, r = len - 1;
-        while(l < r) {
-            const sum = nums[i] + nums[l] + nums[r];
-            if(sum < 0) { l++; continue };
-            if(sum > 0) { r--; continue };
-            resSet.add(`${nums[i]},${nums[l]},${nums[r]}`);
-            l++;
-            r--;
-        }
-    }
-    return Array.from(resSet).map(i => i.split(","));
-};
-
-// 去重优化
 var threeSum = function(nums) {
-    const len = nums.length;
-    if(len < 3) return [];
-    nums.sort((a, b) => a - b);
-    const res = [];
-    for(let i = 0; i < len - 2; i++) {
-        if(nums[i] > 0) break;
-        // a去重
-        if(i > 0 && nums[i] === nums[i - 1]) continue;
-        let l = i + 1, r = len - 1;
+    const res = [], len = nums.length
+    // 将数组排序
+    nums.sort((a, b) => a - b)
+    for (let i = 0; i < len; i++) {
+        let l = i + 1, r = len - 1, iNum = nums[i]
+        // 数组排过序，如果第一个数大于0直接返回res
+        if (iNum > 0) return res
+        // 去重
+        if (iNum == nums[i - 1]) continue
         while(l < r) {
-            const sum = nums[i] + nums[l] + nums[r];
-            if(sum < 0) { l++; continue };
-            if(sum > 0) { r--; continue };
-            res.push([nums[i], nums[l], nums[r]])
-            // b c 去重 
-            while(l < r && nums[l] === nums[++l]);
-            while(l < r && nums[r] === nums[--r]);
+            let lNum = nums[l], rNum = nums[r], threeSum = iNum + lNum + rNum
+            // 三数之和小于0，则左指针向右移动
+            if (threeSum < 0) l++ 
+            else if (threeSum > 0) r--
+            else {
+                res.push([iNum, lNum, rNum])
+                // 去重
+                while(l < r && nums[l] == nums[l + 1]){
+                    l++
+                }
+                while(l < r && nums[r] == nums[r - 1]) {
+                    r--
+                }
+                l++
+                r--
+            }
         }
     }
-    return res;
+    return res
 };
 ```
 TypeScript:

problems/0131.分割回文串.md

@@ -454,31 +454,36 @@ var partition = function(s) {
 
 ```typescript
 function partition(s: string): string[][] {
-    function isPalindromeStr(s: string, left: number, right: number): boolean {
-        while (left < right) {
-            if (s[left++] !== s[right--]) {
-                return false;
+    const res: string[][] = []
+    const path: string[] = []
+    const isHuiwen = (
+        str: string, 
+        startIndex: number, 
+        endIndex: number
+        ): boolean => {
+        for (; startIndex < endIndex; startIndex++, endIndex--) {
+            if (str[startIndex] !== str[endIndex]) {
+                return false
             }
         }
-        return true;
+        return true
     }
-    function backTracking(s: string, startIndex: number, route: string[]): void {
-        let length: number = s.length;
-        if (length === startIndex) {
-            resArr.push(route.slice());
-            return;
+    const rec = (str: string, index: number): void => {
+        if (index >= str.length) {
+            res.push([...path])
+            return
         }
-        for (let i = startIndex; i < length; i++) {
-            if (isPalindromeStr(s, startIndex, i)) {
-                route.push(s.slice(startIndex, i + 1));
-                backTracking(s, i + 1, route);
-                route.pop();
+        for (let i = index; i < str.length; i++) {
+            if (!isHuiwen(str, index, i)) {
+               continue
             }
+            path.push(str.substring(index, i + 1))
+            rec(str, i + 1)
+            path.pop()
         }
     }
-    const resArr: string[][] = [];
-    backTracking(s, 0, []);
-    return resArr;
+    rec(s, 0)
+    return res
 };
 ```