栈，是一种遵循后进先出（LIFO）原则的有序集合。
队列，是一种遵循先进先出（FIFO）原则的有序集合。
在 JavaScript 中，我们可以通过数组相关的方法很容易的扩展出这两种数据结构。
栈的 JavaScript 代码实现：
/**
* Initialize your data structure here.
*/
var MyStack = function() {
this._data = [];
};
/**
* Push element x onto stack.
* @param {number} x
* @return {void}
*/
MyStack.prototype.push = function(x) {
this._data.push(x);
};
/**
* Removes the element on top of the stack and returns that element.
* @return {number}
*/
MyStack.prototype.pop = function() {
return this._data.pop();
};
/**
* Get the top element.
* @return {number}
*/
MyStack.prototype.top = function() {
return this._data[this._data.length -1];
};
/**
* Returns whether the stack is empty.
* @return {boolean}
*/
MyStack.prototype.empty = function() {
return this._data.length === 0;
};
/**
* Your MyStack object will be instantiated and called as such:
* var obj = new MyStack()
* obj.push(x)
* var param_2 = obj.pop()
* var param_3 = obj.top()
* var param_4 = obj.empty()
*/
队列的 JavaScript 代码实现：
/**
* Initialize your data structure here.
*/
var MyQueue = function() {
this._queue = [];
};
/**
* Push element x to the back of queue.
* @param {number} x
* @return {void}
*/
MyQueue.prototype.push = function(x) {
this._queue.push(x);
};
/**
* Removes the element from in front of queue and returns that element.
* @return {number}
*/
MyQueue.prototype.pop = function() {
return this._queue.shift();
};
/**
* Get the front element.
* @return {number}
*/
MyQueue.prototype.peek = function() {
return this._queue[0];
};
/**
* Returns whether the queue is empty.
* @return {boolean}
*/
MyQueue.prototype.empty = function() {
return this._queue.length === 0;
};
/**
* Your MyQueue object will be instantiated and called as such:
* var obj = new MyQueue()
* obj.push(x)
* var param_2 = obj.pop()
* var param_3 = obj.peek()
* var param_4 = obj.empty()
*/