225. 用队列实现栈

  1.     Queue<Integer> queue;
  3.     /** Initialize your data structure here. */
  4.     public MyStack() {
  5.         queue = new LinkedList<Integer>();
  6.     }
  8.     /** Push element x onto stack. */
  9.     public void push(int x) {
  10.         int n = queue.size();
  11.         queue.offer(x);
  12.         for (int i = 0; i < n; i++) {
  13.             queue.offer(queue.poll());///头出尾进
  14.         }
  15.     }
  17.     /** Removes the element on top of the stack and returns that element. */
  18.     public int pop() {
  19.         return queue.poll();
  20.     }
  22.     /** Get the top element. */
  23.     public int top() {
  24.         return queue.peek();
  25.     }
  27.     /** Returns whether the stack is empty. */
  28.     public boolean empty() {
  29.         return queue.isEmpty();
  30.     }
  32. 作者：LeetCode-Solution
  33. 链接：https://leetcode-cn.com/problems/implement-stack-using-queues/solution/yong-dui-lie-shi-xian-zhan-by-leetcode-solution/
  34. 来源：力扣（LeetCode）
  35. 著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。