Submission #952301

#	Time	Username	Problem	Language	Result	Execution time	Memory
952301		vjudge306	Cryptography (NOI20_crypto)	C++17	100 / 100	348 ms	21152 KiB

Crypto

#include <bits/stdc++.h>
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>
#define nn "\n"
#define x_x ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define intt int _; cin >> _; while (_--)
#define emp push_back
#define mod 1000000007
#define all(v) v.begin(), v.end()
#define ld long double
#define A first
#define B second
//#define int long long
typedef long long ll;
const ld eps = 1e-27;
// diff between decimals 0.000000001 mt19937 mt(time(nullptr));

int main() {

    x_x
    int n; cin>>n; int ar[n]; ordered_set s; ll fac[n+2], ans=1; fac[0]=fac[1]=1;
    for (auto&i:ar) cin>>i, s.insert(i);
    for (ll i=2; i<=n; i++) fac[i]=(fac[i-1]*i)%mod;
    fac[n]=0;
    for (int i=0; i<n; i++) {
        auto it=s.lower_bound(ar[i]); s.erase(it);
        ll k=s.order_of_key(ar[i]);
        k=(k*fac[n-i-1])%mod;
        ans=(ans+k)%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