24 -【leetcode】用队列实现栈

[asdzxc01]

https://leetcode-cn.com/problems/implement-stack-using-queues/

[OceanApart]

/**
 * Initialize your data structure here.
 */
var MyStack = function() {
  // 存数据的队列
  this.queue = []
};

/**
 * Push element x onto stack. 
 * @param {number} x
 * @return {void}
 */
MyStack.prototype.push = function(x) {
  var length = this.queue.length

  // 新元素放入队尾
  this.queue.push(x)

  // 旧元素依次出队重新压入队尾，即反转顺序
  while(length--) {
    this.queue.push(this.queue.shift())
  }
};

/**
 * Removes the element on top of the stack and returns that element.
 * @return {number}
 */
MyStack.prototype.pop = function() {
  return this.queue.shift()
};

/**
 * Get the top element.
 * @return {number}
 */
MyStack.prototype.top = function() {
  return this.queue[ 0 ]
};

/**
 * Returns whether the stack is empty.
 * @return {boolean}
 */
MyStack.prototype.empty = function() {
  return this.queue.length === 0
};

[Brand0n-Zhang]

/**
 * 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.unshift(x)
};

/**
 * Removes the element on top of the stack and returns that element.
 * @return {number}
 */
MyStack.prototype.pop = function () {
  return this.queue.shift()
};

/**
 * Get the top element.
 * @return {number}
 */
MyStack.prototype.top = function () {
  return this.queue[0]
};

/**
 * Returns whether the stack is empty.
 * @return {boolean}
 */
MyStack.prototype.empty = function () {
  return this.queue.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()
 */

[tradyau]

/**
 * Initialize your data structure here.
 */
var MyStack = function() {
    this.list = []
};

/**
 * Push element x onto stack. 
 * @param {number} x
 * @return {void}
 */
MyStack.prototype.push = function(x) {
    this.list[this.list.length] = x
};

/**
 * Removes the element on top of the stack and returns that element.
 * @return {number}
 */
MyStack.prototype.pop = function() {
    return this.list.splice(this.list.length - 1, 1)
};

/**
 * Get the top element.
 * @return {number}
 */
MyStack.prototype.top = function() {
    return this.list[this.list.length - 1]
};

/**
 * Returns whether the stack is empty.
 * @return {boolean}
 */
MyStack.prototype.empty = function() {
    return !this.list.length;
};

/**
 * 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()
 */

[xieshiyi]

/**
 * Initialize your data structure here.
 */
var MyStack = function() {
    this.queue = []
    this._queue = []
};

/**
 * Push element x onto stack. 
 * @param {number} x
 * @return {void}
 */
MyStack.prototype.push = function(x) {
    this._queue.push(x)
    while(this.queue.length) {
        this._queue.push(this.queue.shift())
    }
    let swap = this.queue
    this.queue = this._queue
    this._queue = swap
};

/**
 * Removes the element on top of the stack and returns that element.
 * @return {number}
 */
MyStack.prototype.pop = function() {
   return this.queue.shift()
};

/**
 * Get the top element.
 * @return {number}
 */
MyStack.prototype.top = function() {
   return this.queue[0]
};

/**
 * Returns whether the stack is empty.
 * @return {boolean}
 */
MyStack.prototype.empty = function() {
 return !this.queue.length
};

/**
 * 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()
 */

[asdzxc01]

      /**
       * Initialize your data structure here.
       */
      let MyStack = function() {
        this.queue = []
        // 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() {
        return this.queue.splice(-1)
      }

      /**
       * Get the top element.
       * @return {number}
       */
      MyStack.prototype.top = function() {
        return this.queue[this.queue.length - 1]
      }

      /**
       * Returns whether the stack is empty.
       * @return {boolean}
       */
      MyStack.prototype.empty = function() {
        return !this.queue.length
      }

[wucuiping]

/**
 * Initialize your data structure here.
 */
var MyStack = function() {
    this.q = new Array()
};

/**
 * Push element x onto stack. 
 * @param {number} x
 * @return {void}
 */
MyStack.prototype.push = function(x) {
    this.q.push(x)
};

/**
 * Removes the element on top of the stack and returns that element.
 * @return {number}
 */
MyStack.prototype.pop = function() {
    if (this.q.length > 0) {
        return this.q.pop()
    }
};

/**
 * Get the top element.
 * @return {number}
 */
MyStack.prototype.top = function() {
    if (this.q.length > 0) {
        return this.q[this.q.length - 1]
    }
};

/**
 * Returns whether the stack is empty.
 * @return {boolean}
 */
MyStack.prototype.empty = function() {
    if (this.q.length < 1) {
        return true
    }
    return false
};

/**
 * 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()
 */