代码随想录算法训练营第10天|232.用栈实现队列,225. 用队列实现栈

class MyQueue {
private:
    stack<int> stIn;
    stack<int> stOut;   
public:
    MyQueue() {
    }
    void push(int x) {
        stIn.push(x);
    }
    int pop() {
        while(stOut.empty()){
            while(!stIn.empty()){
                stOut.push(stIn.top());
                stIn.pop();
            }
        }
        int val = stOut.top();
        stOut.pop();
        return val;
    }
    int peek() {
        int val = this->pop();
        stOut.push(val);
        return val;
    }
    bool empty() {
        return stIn.empty() && stOut.empty();
    }
};
/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue* obj = new MyQueue();
 * obj->push(x);
 * int param_2 = obj->pop();
 * int param_3 = obj->peek();
 * bool param_4 = obj->empty();
 */

class MyStack {
private:
    queue<int> queue1;
public:
    MyStack() {
    }
    void push(int x) {
        queue1.push(x);
    }
    int pop() {
        int size = queue1.size()-1;
        while(size--){
            queue1.push(queue1.front());
            queue1.pop();
        }
        int val = queue1.front();
        queue1.pop();
        return val;
    }
    int top() {
        return queue1.back();
    }
    bool empty() {
       return  queue1.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();
 */