Submission #329801

#	Time	Username	Problem	Language	Result	Execution time	Memory
329801		JiratQ	Cryptography (NOI20_crypto)	C++14	48 / 100	1091 ms	50080 KiB

Crypto

#include<bits/stdc++.h>
#define int long long
using namespace std;
int dp[300010];

int fac(int n){
    if(dp[n]!=0) return dp[n];
    if(n==0) return 1;
    return dp[n]=(fac(n-1)%1000000007*n);
}

main(){
    int n;
    cin >> n;
    vector<int> vec;
    for(int i=0;i<n;i++){
        int k;
        scanf("%lld",&k);
        vec.emplace_back(k);
    }
    vector<int> v=vec;
    sort(v.begin(),v.end());
    unordered_map<int,int> mapp;
    int cnt=1;
    for(int i=0;i<n;i++){
        mapp[v[i]]=cnt;
        cnt++;
    }
    for(int i=0;i<n;i++){
        vec[i]=mapp[vec[i]];
    }
    map<int,int> m;
    int ans=1;
    for(int i=0;i<n;i++){
        int use=vec[i];
        int c=0;
        for(auto& k:m){
            if(use>k.first){
                c++;
            }
            else break;
        }
        m[use]=1;
        ans += ((use-1-c) * fac(n-1-i));
        ans %= 1000000007;
    }
    cout << ans;
}
//

Compilation message (stderr)

Crypto.cpp:12:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   12 | main(){
      |      ^
Crypto.cpp: In function 'int main()':
Crypto.cpp:18:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   18 |         scanf("%lld",&k);
      |         ~~~~~^~~~~~~~~~~

• 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