题目要求

思路讲解

栈：先进后出
队列：先进先出

代码展示

#include <iostream>using namespace std;const int N = 100010;int m;
int stk[N], tt;int main()
{cin >> m;while (m -- ){string op;int x;cin >> op;if (op == "push"){cin >> x;stk[ ++ tt] = x;}else if (op == "pop") tt -- ;else if (op == "empty") cout << (tt ? "NO" : "YES") << endl;else cout << stk[tt] << endl;}return 0;
}