Implement Queue using Stacks.java

// Runtime: 1 ms (Top 70.23%) | Memory: 41.5 MB (Top 77.34%)
class MyQueue {

    private final Deque<Integer> stack = new ArrayDeque<>();
    private final Deque<Integer> temp = new ArrayDeque<>();

    /**
     * Initialize your data structure here.
     */
    public MyQueue() {}

    /**
     * Pushes element x to the back of the queue.
     */
    public void push(int x) {
        stack.push(x);
    }

    /**
     * @return the element at the front of the queue and remove it.
     */
    public int pop() {
        while (stack.size() > 1)
            temp.push(stack.pop());

        var val = stack.pop();
        while (!temp.isEmpty())
            stack.push(temp.pop());

        return val;
    }

    /**
     * @return the element at the front of the queue.
     */
    public int peek() {
        while (stack.size() > 1)
            temp.push(stack.pop());

        var val = stack.peek();
        while (!temp.isEmpty())
            stack.push(temp.pop());

        return val;
    }

    /**
     * @return true if the queue is empty, false otherwise.
     */
    public boolean empty() {
        return stack.isEmpty();
    }
}