Implement Stack using Queues

Description

Implement the following operations of a stack using queues.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• empty() -- Return whether the stack is empty.

Example:

MyStack stack = new MyStack();
stack.push(1);
stack.push(2);

stack.top();   // returns 2
stack.pop();   // returns 2
stack.empty(); // returns false

Notes:

• You must use only standard operations of a queue -- which means only push to back, peek/pop from front, size, and is empty operations are valid.
• Depending on your language, queue may not be supported natively. You may simulate a queue by using a list or deque (double-ended queue), as long as you use only standard operations of a queue.
• You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack).

Solution(javascript)

const Queue = () => {
  const queue = []
  return {
    get length() {
      return queue.length
    },
    push: x => queue.push(x),
    pop: () => queue.shift(),
    top: () => queue[0],
  }
}
const MyStack = function () {
  this.queue = Queue()
}

/**
 * Push element x onto stack.
 * @param {number} x
 * @return {void}
 */
MyStack.prototype.push = function (x) {
  if (this.queue.length === 0) {
    this.queue.push(x)
  } else {
    this.queue.push(x)
    for (let i = 1; i <= this.queue.length - 1; i++) {
      this.queue.push(this.queue.pop())
    }
  }
}

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

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

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