Merge pull request #263 from flames519/master

0232,0225,0020,1047,0150JavaScript版本

problems/0020.有效的括号.md

@@ -271,6 +271,23 @@ var isValid = function (s) {
   }
   return stack.length === 0;
 };
+// 简化版本
+var isValid = function(s) {
+    const stack = [], 
+        map = {
+            "(":")",
+            "{":"}",
+            "[":"]"
+        };
+    for(const x of s) {
+        if(x in map) {
+            stack.push(x);
+            continue;
+        };
+        if(map[stack.pop()] !== x) return false;
+    }
+    return !stack.length;
+};
 ```
 
 

problems/0150.逆波兰表达式求值.md

@@ -197,6 +197,32 @@ func evalRPN(tokens []string) int {
 }
 ```
 
+javaScript:
+
+```js
+
+/**
+ * @param {string[]} tokens
+ * @return {number}
+ */
+var evalRPN = function(tokens) {
+    const s = new Map([
+        ["+", (a, b) => a * 1  + b * 1],
+        ["-", (a, b) => b - a],
+        ["*", (a, b) => b * a],
+        ["/", (a, b) => (b / a) | 0]
+    ]);
+    const stack = [];
+    for (const i of tokens) {
+        if(!s.has(i)) {
+            stack.push(i);
+            continue;
+        }
+        stack.push(s.get(i)(stack.pop(),stack.pop()))
+    }
+    return stack.pop();
+};
+```
 
 
 -----------------------

problems/0225.用队列实现栈.md

@@ -357,8 +357,115 @@ class MyStack:
 
 Go：
 
+javaScript: 
 
+使用数组（push, shift）模拟队列
 
+```js
+
+// 使用两个队列实现
+/**
+ * Initialize your data structure here.
+ */
+var MyStack = function() {
+    this.queue1 = [];
+    this.queue2 = [];
+};
+
+/**
+ * Push element x onto stack. 
+ * @param {number} x
+ * @return {void}
+ */
+MyStack.prototype.push = function(x) {
+    this.queue1.push(x);
+};
+
+/**
+ * Removes the element on top of the stack and returns that element.
+ * @return {number}
+ */
+MyStack.prototype.pop = function() {
+    // 减少两个队列交换的次数， 只有当queue1为空时，交换两个队列
+    if(!this.queue1.length) {
+        [this.queue1, this.queue2] = [this.queue2, this.queue1];
+    }
+    while(this.queue1.length > 1) {
+        this.queue2.push(this.queue1.shift());
+    }
+    return this.queue1.shift();
+};
+
+/**
+ * Get the top element.
+ * @return {number}
+ */
+MyStack.prototype.top = function() {
+    const x = this.pop();
+    this.queue1.push(x);
+    return x;
+};
+
+/**
+ * Returns whether the stack is empty.
+ * @return {boolean}
+ */
+MyStack.prototype.empty = function() {
+    return !this.queue1.length && !this.queue2.length;
+};
+
+```
+
+```js
+
+// 使用一个队列实现
+/**
+ * Initialize your data structure here.
+ */
+var MyStack = function() {
+    this.queue = [];
+};
+
+/**
+ * Push element x onto stack. 
+ * @param {number} x
+ * @return {void}
+ */
+MyStack.prototype.push = function(x) {
+    this.queue.push(x);
+};
+
+/**
+ * Removes the element on top of the stack and returns that element.
+ * @return {number}
+ */
+MyStack.prototype.pop = function() {
+    let size = this.queue.length;
+    while(size-- > 1) {
+        this.queue.push(this.queue.shift());
+    }
+    return this.queue.shift();
+};
+
+/**
+ * Get the top element.
+ * @return {number}
+ */
+MyStack.prototype.top = function() {
+    const x = this.pop();
+    this.queue.push(x);
+    return x;
+};
+
+/**
+ * Returns whether the stack is empty.
+ * @return {boolean}
+ */
+MyStack.prototype.empty = function() {
+    return !this.queue.length;
+};
+
+```
 
 -----------------------
 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)

problems/0232.用栈实现队列.md

@@ -353,6 +353,61 @@ func (this *MyQueue) Empty() bool {
  */
  ```
 
+ javaScript:
+
+ ```js
+ // 使用两个数组的栈方法（push, pop） 实现队列
+ /**
+ * Initialize your data structure here.
+ */
+var MyQueue = function() {
+    this.stack1 = [];
+    this.stack2 = [];
+};
+
+/**
+ * Push element x to the back of queue. 
+ * @param {number} x
+ * @return {void}
+ */
+MyQueue.prototype.push = function(x) {
+    this.stack1.push(x);
+};
+
+/**
+ * Removes the element from in front of queue and returns that element.
+ * @return {number}
+ */
+MyQueue.prototype.pop = function() {
+    const size = this.stack2.length;
+    if(size) {
+        return this.stack2.pop();
+    }
+    while(this.stack1.length) {
+        this.stack2.push(this.stack1.pop());
+    }
+    return this.stack2.pop();
+};
+
+/**
+ * Get the front element.
+ * @return {number}
+ */
+MyQueue.prototype.peek = function() {
+    const x = this.pop();
+    this.stack2.push(x);
+    return x;
+};
+
+/**
+ * Returns whether the queue is empty.
+ * @return {boolean}
+ */
+MyQueue.prototype.empty = function() {
+    return !this.stack1.length && !this.stack2.length
+};
+ ```
+
 
 
 

problems/1047.删除字符串中的所有相邻重复项.md

@@ -186,6 +186,24 @@ class Solution:
 
 Go：
 
+javaScript: 
+
+```js
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var removeDuplicates = function(s) {
+    const stack = [];
+    for(const x of s) {
+        let c = null;
+        if(stack.length && x === (c = stack.pop())) continue;
+        c && stack.push(c);
+        stack.push(x);
+    }
+    return stack.join("");
+};
+```