Implement stack using queue!!

we only need one queue 因为queue是两边开口的

• [x] ``` public void push(int x) {

      queue.offer(x);
      for (int i = 0; i < queue.size() - 1; i++) {
          queue.offer(queue.poll()); /************************/
      }
  }
  

class MyStack { //queue 4321 //stack 1234 /* Initialize your data structure here. / Queue queue; public MyStack() { queue = new LinkedList<>(); }

/** Push element x onto stack. */
public void push(int x) {
    queue.offer(x);
    for (int i = 0; i < queue.size() - 1; i++) {
        queue.offer(queue.poll());
    }
}

/** Removes the element on top of the stack and returns that element. */
public int pop() {
    return queue.poll();
}

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

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

}

/**

• Your MyStack object will be instantiated and called as such:
• MyStack obj = new MyStack();
• obj.push(x);
• int param_2 = obj.pop();
• int param_3 = obj.top();
• boolean param_4 = obj.empty(); */ ```