4269.校庆

caution

原题链接：https://www.acwing.com/activity/content/problem/content/7043/

思路

代码

#include <bits/stdc++.h>

using namespace std;

int n, m;
unordered_map<string, int> sch;
vector<string> res;

int main() {
    cin >> n;

    for (int i = 0; i < n; i++) {
        string t;
        cin >> t;
        sch[t] = 1;
    }

    string a, b;

    cin >> m;

    while (m--) {
        string t;
        cin >> t;
        string name = t;
        if (sch.count(t) != 0) {
            res.push_back(t);
            // 记录参加校庆的校友最年长的身份证
            if (a.empty() || a.substr(6, 8) > name.substr(6, 8))
                a = name;
        }
        // 记录出席来宾中最年正的身份证
        if (b.empty() || b.substr(6, 8) > name.substr(6, 8))
            b = name;
    }
    // 输出参加校庆的校友
    cout << res.size() << endl;

    if (res.size()) {
        cout << a << endl;
    } else {
        cout << b << endl;
    }

    return 0;
}