Submission #733813

#	Time	Username	Problem	Language	Result	Execution time	Memory
733813		vjudge1	Cryptography (NOI20_crypto)	C++17	48 / 100	1070 ms	6720 KiB

Crypto

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int mod = 1e9 + 7;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    auto b = a;
    sort(b.begin(), b.end());
    for (int i = 0; i < n; i++) {
        a[i] = lower_bound(b.begin(), b.end(), a[i]) - b.begin();
    }
    vector<int> fac(n + 1);
    fac[0] = 1;
    for (int i = 1; i <= n; i++) {
        fac[i] = 1LL * fac[i - 1] * i % mod;
    }
    int ans = 1;
    for (int i = 0; i < n; i++) {
        ans = (ans + 1LL * (a[i] - i) * fac[n - i - 1] % mod) % mod;
        for (int j = i + 1; j < n; j++) {
            if (a[j] < a[i]) {
                a[j]++;
            }
        }
    }
    cout << ans << "\n";
    return 6/22;
}

• Subtask 1: 5 / 5
• Subtask 2: 9 / 9
• Subtask 3: 0 / 10
• Subtask 4: 0 / 11
• Subtask 5: 21 / 21
• Subtask 6: 13 / 13
• Subtask 7: 0 / 19
• Subtask 8: 0 / 12