Implement Stack using Queues

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.


MyStack stack = new MyStack();

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


  • You must use only standard operations of a queue — which means only push to backpeek/pop from frontsize, 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).


public class MyStack {
    Queue queue;
    /** Initialize your data structure here. */
    public MyStack() {
        queue = new Queue();
    /** Push element x onto stack. */
    public void Push(int x) {
        for(int i=0;i<queue.Count-1;i++)
    /** Removes the element on top of the stack and returns that element. */
    public int Pop() {
        return (int)(queue.Dequeue());
    /** Get the top element. */
    public int Top() {
        return (int)(queue.Peek());
    /** Returns whether the stack is empty. */
    public bool Empty() {
        return queue.Count == 0;
 * Your MyStack object will be instantiated and called as such:
 * MyStack obj = new MyStack();
 * obj.Push(x);
 * int param_2 = obj.Pop();
 * int param_3 = obj.Top();
 * bool param_4 = obj.Empty();

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