LeetCode Implement Queue using Stacks

Description:

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.

Solution:

和MyStack一样的做法。

import java.util.*;

class MyQueue {
	Stack stack = new Stack();

	// Push element x to the back of queue.
	public void push(int x) {
		Stack temp = new Stack();
		while (!stack.isEmpty())
			temp.push(stack.pop());
		stack.push(x);
		while (!temp.isEmpty())
			stack.push(temp.pop());
	}

	// Removes the element from in front of queue.
	public void pop() {
		stack.pop();
	}

	// Get the front element.
	public int peek() {
		return stack.peek();
	}

	// Return whether the queue is empty.
	public boolean empty() {
		return stack.isEmpty();
	}
}