力扣-225题用队列实现栈（C++）

缺乏、安全感 2022-09-12 01:49 163阅读 0赞

题目链接：[https://leetcode-cn.com/problems/implement-stack-using-queues/][https_leetcode-cn.com_problems_implement-stack-using-queues]  
题目如下：  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16]  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16 1]

class MyStack {
        
    public:
        //思路：一个队列在模拟栈弹出元素的时候只要将队列头部的元素（除了最后一个元素外） 重新添加到队列尾部
        queue<int> que;
        int count=0;
        /** Initialize your data structure here. */
        MyStack() {
        
    
        }
        
        /** Push element x onto stack. */
        void push(int x) {
        
            que.push(x);
            count++;
        }
        
        /** Removes the element on top of the stack and returns that element. */
        int pop() {
        
            for(int i=0;i<count-1;i++){
        
                que.push(que.front());
                que.pop();
            }
    
            int num=que.front();
            que.pop();
            count--;
    
            return num;
        }
        
        /** Get the top element. */
        int top() {
        
            for(int i=0;i<count-1;i++){
        
                que.push(que.front());
                que.pop();
            }
    
            int num=que.front();
            que.push(num);
            que.pop();
    
            return num;
        }
        
        /** Returns whether the stack is empty. */
        bool empty() {
        
            return que.empty();
        }
    };
    
    /**
     * 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();
     * bool param_4 = obj->empty();
     */

[https_leetcode-cn.com_problems_implement-stack-using-queues]: https://leetcode-cn.com/problems/implement-stack-using-queues/
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/d3959d434a0e43cd8847f96a1914245f.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220828/37cc1082b5a34ce18faf6cfb55a4e201.png