232. Implement Queue using Stacks && 225. Implement Stack using Queues

class MyQueue {
    Deque<Integer> stack = new ArrayDeque<Integer>();
    // Push element x to the back of queue.
    public void push(int x) {
        //Organize at push stage becasue peek needs to see the top.
        Deque<Integer> temp = new ArrayDeque<Integer>();
        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();
    }
}

class MyStack {
    Deque<Integer> queue = new ArrayDeque<Integer>();
    // Push element x onto stack.
    public void push(int x) {
       queue.add(x);
       for(int i=0;i<queue.size()-1;i++) {
           queue.add(queue.poll());
       }
    }

    // Removes the element on top of the stack.
    public void pop() {
        queue.poll();
    }

    // Get the top element.
    public int top() {
        return queue.peek();
    }

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