Submission #1113812

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113812		Aviansh	Cryptography (NOI20_crypto)	C++17	100 / 100	465 ms	26980 KiB

Crypto

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;

using namespace std;

typedef tree<long long,null_type,less<long long>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

long long fac[300005];
long long mod = 1e9+7;

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    fac[1]=1;
    for(long long i = 2;i<=3e5;i++){
        fac[i]=fac[i-1]*i;
        fac[i]%=mod;
    }
    long long n;
    cin >> n;
    long long arr[n];
    ordered_set pts;
    for(long long i = 0;i<n;i++){
        cin >> arr[i];
        pts.insert(arr[i]);
    }

    long long ans = 0;
    for(long long i = 0;i<n;i++){
        ans+=1LL*pts.order_of_key(arr[i])*fac[n-i-1];
        ans%=mod;
        pts.erase(arr[i]);
    }
    ans++;
    ans%=mod;
    cout << ans;
    return 0;
}

• 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