Author: lllyouo
Date: 20250818
tag: 栈
link: https://www.luogu.com.cn/problem/P1165

问题描述

link

分析

略

参考代码

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

int st[200010], top = -1;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int N; cin >> N;
    
    st[++top] = 0;
    while (N--) {
        int op, ans = 0; cin >> op;
        if (op == 0) {
            int x; cin >> x;
            st[++top] = max(st[top], x);
        } else if (op == 1) {
            if (top >= 0) top--;
        } else if (op == 2) {
            cout << st[top] << endl;
        }
    }
    
    return 0;
}