Implement Queue using Stacks

Implement the following operations of a queue using stacks.

• push(x) -- Push element x to the back of queue.
• pop() -- Removes the element from in front of queue.
• peek() -- Get the front element.
• empty() -- Return whether the queue is empty.

Notes:

• You must use only standard operations of a stack -- which means only push to top, peek/pop from top, size, and is empty operations are valid.
• Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack.
• You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue).

class MyQueue {

    

    Stack<Integer> stk1 = new Stack<Integer>();

    Stack<Integer> stk2 = new Stack<Integer>();

    

    // Push element x to the back of queue.

    public void push(int x) {

        while (!stk2.isEmpty()) {

            stk1.push(stk2.pop());

        }    

        stk1.push(x);

        while (!stk1.isEmpty()) {

            stk2.push(stk1.pop());

        }

    }

    // Removes the element from in front of queue.

    public void pop() {

        stk2.pop();

    }

    // Get the front element.

    public int peek() {

        return stk2.peek();

    }

    // Return whether the queue is empty.

    public boolean empty() {

        return stk2.isEmpty();

    }

}