Merge pull request youngyangyang04#1232 from Jamcy123/master

修改 0503.下一个更大元素II javascript 版本、修改版本一、增加版本二 0739.每日温度 javascript 版本

Author: youngyangyang04

problems/0503.下一个更大元素II.md

@@ -166,20 +166,19 @@ JavaScript:
  * @return {number[]}
  */
 var nextGreaterElements = function (nums) {
-  // let map = new Map();
+  const len = nums.length;
   let stack = [];
-  let res = new Array(nums.length).fill(-1);
-  for (let i = 0; i < nums.length * 2; i++) {
+  let res = Array(len).fill(-1);
+  for (let i = 0; i < len * 2; i++) {
     while (
       stack.length &&
-      nums[i % nums.length] > nums[stack[stack.length - 1]]
+      nums[i % len] > nums[stack[stack.length - 1]]
     ) {
-      let index = stack.pop();
-      res[index] = nums[i % nums.length];
+      const index = stack.pop();
+      res[index] = nums[i % len];
     }
-    stack.push(i % nums.length);
+    stack.push(i % len);
   }
-
   return res;
 };
 ```

problems/0739.每日温度.md

@@ -301,32 +301,46 @@ func dailyTemperatures(num []int) []int {
 
 JavaScript：
 ```javascript
-/**
- * @param {number[]} temperatures
- * @return {number[]}
- */
+// 版本一
 var dailyTemperatures = function(temperatures) {
-    let n = temperatures.length;
-    let res = new Array(n).fill(0);
-    let stack = [];  // 递减栈：用于存储元素右面第一个比他大的元素下标
+    const n = temperatures.length;
+    const res = Array(n).fill(0);
+    const stack = [];  // 递增栈：用于存储元素右面第一个比他大的元素下标
     stack.push(0);
     for (let i = 1; i < n; i++) {
         // 栈顶元素
-        let top = stack[stack.length - 1];
+        const top = stack[stack.length - 1];
         if (temperatures[i] < temperatures[top]) {
             stack.push(i);
         } else if (temperatures[i] === temperatures[top]) {
             stack.push(i);
         } else {
             while (stack.length && temperatures[i] > temperatures[stack[stack.length - 1]]) {
-                let top = stack.pop();
+                const top = stack.pop();
                 res[top] = i - top;
             }
             stack.push(i);
         }
     }
     return res;
 };
+
+
+// 版本二
+var dailyTemperatures = function(temperatures) {
+    const n = temperatures.length;
+    const res = Array(n).fill(0);
+    const stack = [];  // 递增栈：用于存储元素右面第一个比他大的元素下标
+    stack.push(0);
+    for (let i = 1; i < n; i++) {
+        while (stack.length && temperatures[i] > temperatures[stack[stack.length - 1]]) {
+            const top = stack.pop();
+            res[top] = i - top;
+        }
+        stack.push(i);
+    }
+    return res;
+};
 ```
 
 

problems/1047.删除字符串中的所有相邻重复项.md

@@ -250,11 +250,9 @@ func removeDuplicates(s string) string {
 
 javaScript: 
 
+法一：使用栈
+
 ```js
-/**
- * @param {string} s
- * @return {string}
- */
 var removeDuplicates = function(s) {
     const stack = [];
     for(const x of s) {
@@ -267,6 +265,25 @@ var removeDuplicates = function(s) {
 };
 ```
 
+法二：双指针（模拟栈）
+
+```js
+// 原地解法（双指针模拟栈）
+var removeDuplicates = function(s) {
+    s = [...s];
+    let top = -1; // 指向栈顶元素的下标
+    for(let i = 0; i < s.length; i++) {
+        if(top === -1 || s[top] !== s[i]) { // top === -1 即空栈
+            s[++top] = s[i]; // 入栈
+        } else {
+            top--; // 推出栈
+        }
+    }
+    s.length = top + 1; // 栈顶元素下标 + 1 为栈的长度
+    return s.join('');
+};
+```
+
 TypeScript：
 
 ```typescript