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_0232_Implement_Queue_using_Stacks.java
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_0232_Implement_Queue_using_Stacks.java
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// https://leetcode.com/problems/implement-queue-using-stacks/
import java.util.*;
public class _0232_Implement_Queue_using_Stacks {
public static void main(String[] args)
{
MyQueue obj = new MyQueue();
obj.push(1);
obj.push(2);
// System.out.println(obj.top());
System.out.println(obj.peek());
System.out.println(obj.pop());
System.out.println(obj.empty());
}
}
class MyQueue {
Stack<Integer> queue;
Stack<Integer> temp;
public MyQueue() {
queue = new Stack<>();
temp = new Stack<>();
}
public void push(int x)
{
queue.push(x);
}
public int pop()
{
if(queue.isEmpty())
{
return -1;
}
while(!queue.isEmpty())
{
temp.push(queue.pop());
}
int ans = temp.pop();
while(!temp.isEmpty())
{
queue.push(temp.pop());
}
return ans;
}
public int peek()
{
if(queue.isEmpty())
{
return -1;
}
while(!queue.isEmpty())
{
temp.push(queue.pop());
}
int ans = temp.peek();
while(!temp.isEmpty())
{
queue.push(temp.pop());
}
return ans;
}
public boolean empty() {
return queue.isEmpty();
}
}