Submission #888907

#	Time	Username	Problem	Language	Result	Execution time	Memory
888907		vjudge1	Cryptography (NOI20_crypto)	C++17	100 / 100	411 ms	19580 KiB

Crypto

#include <iostream>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
long long int a[300005], f[300005], mod = 1e9 + 7;
int main() {
    int n;
    cin >> n;
    ordered_set s;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        s.insert(a[i]);
    }
    f[n + 1] = 1;
    for (int i = n; i >= 1; i--) {
        f[i] = f[i + 1] * (n - i + 1) % mod;
    }
    long long int res = 0;
    for (int i = 1; i <= n; i++) {
        res = (res + s.order_of_key(a[i]) * f[i + 1]) % mod;
        s.erase(s.find(a[i]));
    }
    cout << (res + 1) % mod;
}

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