using System;
using System.Collections.Generic;
class MainClass
{
public static void Main()
{
MyQueue q = new MyQueue();
q.Push(1);
q.Push(2);
//Console.WriteLine(q.Peek());
//Console.WriteLine(q.Pop());
//Console.WriteLine(q.Empty());
//while (!q.Empty())
//{ Console.Write($"{q.Pop()} --> "); }
}
}
public class MyQueue
{
private Stack<int> queueStack;
private Stack<int> helperStack;
public MyQueue()
{
queueStack = new Stack<int>();
helperStack = new Stack<int>();
}
public void Push(int x)
{
queueStack.Push(x); //push to front of queue - fifo
}
public int Pop()
{
Peek(); //does all the organising
return helperStack.Pop();
}
public int Peek()
{
if (helperStack.Count != 0) { return helperStack.Peek(); }
while(queueStack.Count != 0) { helperStack.Push(queueStack.Pop()); }
return helperStack.Peek(); //need to peek at bottom of queue stack as that's the front of the queue
}
public bool Empty()
{
return queueStack.Count == 0 && helperStack.Count == 0;
}
}
