召唤数学精灵 参考代码

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

typedef long long LL;
const int maxn = 100 + 100;

LL sum(LL x) {
    return (1 + x) * x / 2 % 100;
}

LL mult(LL x) {
    LL ret = 1;
    for (LL i = 1; i <= x; ++i) {
        ret = ret * i % 100;
    }
    return ret;
}

int main() {
#ifdef ExRoc
    freopen("test.txt", "r", stdin);
#endif // ExRoc
    ios::sync_with_stdio(false);

    int cnt = 0;
    for (int i = 1; i <= 2000; ++i) {
        if ((sum(i) - mult(i)) % 100 == 0) {
            ++cnt;
            cout << i << ": " << cnt << endl;
        }
    }
    cout << "2024041331404202" << endl;
    cout << "202404133140400" << endl;
    cout <<  "40480826628086" << endl;

    return 0;
}