题目描述

数组模拟栈

C++代码

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int stk[N], t = -1;

bool empty(){
    return t == -1;
}

void push(int x){
    stk[++t] = x;
}

int pop(){
    return stk[t--];
}

int query(){
    return stk[t];
}

int main(){
    int m, x;
    string op;
    cin >> m;
    while(m--){
        cin >> op;
        if(op == "push"){
            cin >> x;
            push(x);
        }
        else if(op == "pop"){
            pop();
        }
        else if(op == "empty"){
            if(empty()){
                cout << "YES" << endl;
            }
            else{
                cout << "NO" << endl;
            }
        }
        else{
            cout << query() << endl;
        }
    }
    return 0;
}