Implement_Queue_using_Stacks.java

package com.leet_code;

import java.util.Stack;

public class Implement_Queue_using_Stacks {
    class MyQueue {
        Stack<Integer> s1;
        Stack<Integer> s2;
        public MyQueue() {
            s1=new Stack<>();
            s2=new Stack<>();
        }
        public void push(int x) {
            s1.push(x);
        }
        public int pop() {
            while (!s1.isEmpty()){
                s2.push(s1.pop());
            }
            int removed=s2.pop();
            while (!s2.isEmpty()){
                s1.push(s2.pop());
            }
            return removed;
        }
        public int peek() {
            while (!s1.isEmpty()){
                s2.push(s1.pop());
            }
            int peeked=s2.peek();
            while (!s2.isEmpty()){
                s1.push(s2.pop());
            }
            return peeked;
        }
        public boolean empty() {
            return s1.isEmpty();
        }
    }
}