题解 | Letter Song ~ 致十年后的我们

#include <iostream>
#include <string>
#include <algorithm> // 若保留reverse则需要，这里可省略
using namespace std;

int main() {
    string s;
    cin >> s;
    string result;
    int year = 0;
    for (int i = 0; i < 4; ++i) {
        year = year * 10 + (s[i] - '0');
    }
    year += 10;
    result = to_string(year) + s.substr(4); 
    cout << result << endl;
    return 0;
}