package Queue;

import java.util.Stack;

public class QueueUsingStacks {

public static void main(String[] args) {

}

private Stack<Integer> first;

private Stack<Integer> second;

public QueueUsingStacks(){

first = new Stack<>();

second = new Stack<>();

}

public void add(int item){

first.push(item);

}

public int remove(){

while (!first.isEmpty()){

second.push(first.pop());

}

int removed = second.pop();

while (!second.isEmpty()){

first.push(second.pop());

}

return removed;

}

public boolean isEmpty(){

return first.isEmpty();

}

public void efficientAdd(int item) throws Exception{

while (!first.isEmpty()){

second.push(first.pop());

}

first.push(item);

while(!second.isEmpty())

first.push(second.pop());

}

public int efficientPeek() throws Exception{

return first.peek();

}

public int peek() throws Exception{

while (!first.isEmpty()){

second.push(first.pop());

}

int peek = second.peek();

while (!second.isEmpty()){

first.push(second.pop());

}

return peek;

}

}