QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#207878 | #5749. Directed Vertex Cacti | xia_mc | RE | 2ms | 9404kb | C++14 | 497b | 2023-10-08 21:56:31 | 2023-10-08 21:56:31 |
Judging History
answer
#include<stdio.h>
#define int long long
const int N=1e6,mod=1e9+9;
int ksm(int x,int y){
int s=1;
while(y){
if(y&1) (s*=x)%=mod;
(x*=x%mod)%=mod;y>>=1;
}
return s;
}
int fact[N];
int inv(int x){return ksm(x,mod-2);}
void init(){fact[0]=1;for(int i=1;i<=N;i++) fact[i]=fact[i-1]*i;}
int C(int n,int m){return fact[n]*inv(fact[n-m])%mod*(inv(fact[m]))%mod;}
int n,m;
signed main(){
init();scanf("%lld%lld",&n,&m);
printf("%lld\n",fact[n]*C(C(n,2),m));
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 9404kb
input:
3 1
output:
18
result:
ok 1 number(s): "18"
Test #2:
score: 0
Accepted
time: 2ms
memory: 9344kb
input:
4 4
output:
360
result:
ok 1 number(s): "360"
Test #3:
score: -100
Runtime Error
input:
39847 348708