Merge pull request #20 from daluozha/main

leetcode 141、206、225，剑指offer 09 补充js版代码

animation-simulation/栈和队列/225.用队列实现栈.md

@@ -18,6 +18,7 @@
 
 下面我们来看一下题目代码，也是很容易理解。
 
+Java Code:
 ```java
 class MyStack {
     //初始化队列
@@ -55,3 +56,34 @@ class MyStack {
 
 ```
 
+JS Code:
+```javascript
+var MyStack = function() {
+    this.queue = [];
+};
+
+MyStack.prototype.push = function(x) {
+    this.queue.push(x);
+    if (this.queue.length > 1) {
+        let i = this.queue.length - 1;
+        while (i) {
+            this.queue.push(this.queue.shift());
+            i--;
+        }
+    }
+};
+
+MyStack.prototype.pop = function() {  
+    return this.queue.shift();
+};
+
+MyStack.prototype.top = function() {
+    return this.empty() ? null : this.queue[0];
+
+};
+
+MyStack.prototype.empty = function() {
+    return !this.queue.length;
+};
+```
+

animation-simulation/栈和队列/剑指Offer09用两个栈实现队列.md

@@ -58,6 +58,7 @@ class CQueue {
 
 大家可以点击该链接[剑指 Offer 09. 用两个栈实现队列](https://leetcode-cn.com/problems/yong-liang-ge-zhan-shi-xian-dui-lie-lcof/)去实现一下，下面我们看代码。
 
+Java Code:
 ```java
 class CQueue {
      //初始化两个栈
@@ -89,3 +90,24 @@ class CQueue {
 }
 ```
 
+JS Code:
+```javascript
+var CQueue = function() {
+    this.stack1 = [];
+    this.stack2 = [];
+};
+
+CQueue.prototype.appendTail = function(value) {
+    this.stack1.push(value);
+};
+
+CQueue.prototype.deleteHead = function() {
+    if (!this.stack2.length) {
+        while(this.stack1.length) {
+            this.stack2.push(this.stack1.pop());
+        }
+    }
+    return this.stack2.pop() || -1;
+};
+```
+

animation-simulation/链表篇/leetcode141环形链表.md

@@ -38,6 +38,7 @@
 
 **题目代码**
 
+Java Code:
 ```java
 public class Solution {
     public boolean hasCycle(ListNode head) {
@@ -56,3 +57,18 @@ public class Solution {
 }
 ```
 
+JS Code:
+```javascript
+var hasCycle = function(head) {
+    let fast = head;
+    let slow = head;
+    while (fast && fast.next) {
+        fast = fast.next.next;
+        slow = slow.next;
+        if (fast === slow) {
+            return true;
+        }
+    }
+    return false;
+};
+```

animation-simulation/链表篇/leetcode206反转链表.md

@@ -33,6 +33,7 @@ low = temp 即可。然后重复执行上诉操作直至最后，这样则完成
 
 我会对每个关键点进行注释，大家可以参考动图理解。
 
+Java Code:
 ```java
 class Solution {
     public ListNode reverseList(ListNode head) {
@@ -62,9 +63,27 @@ class Solution {
 
 }
 ```
+JS Code:
+```javascript
+var reverseList = function(head) {
+    if(!head || !head.next) {
+        return head;
+    }
+    let low = null;
+    let pro = head;
+    while (pro) {
+        let temp = pro;
+        pro = pro.next;
+        temp.next = low;
+        low = temp;
+    }
+    return low;
+};
+```
 
 上面的迭代写法是不是搞懂啦，现在还有一种递归写法，不是特别容易理解，刚开始刷题的同学，可以只看迭代解法。
 
+Java Code:
 ```java
 class Solution {
     public ListNode reverseList(ListNode head) {
@@ -86,3 +105,16 @@ class Solution {
 
 ```
 
+JS Code:
+```javascript
+var reverseList = function(head) {
+    if (!head || !head.next) {
+        return head;
+    }
+    let pro = reverseList(head.next);
+    head.next.next = head;
+    head.next = null;
+    return pro;
+};
+```
+