Submission #20086

#	Time	Username	Problem	Language	Result	Execution time	Memory
20086		gs12117	순열 (kriii4_T)	C++98	100 / 100	1114 ms	1084 KiB

T

#include<stdio.h>
int n,m;
int mod=1000000007;
int mpow(int x,int y){
	if(y==0)return 1;
	long long int r=mpow(x,y/2);
	r*=r;
	r%=mod;
	if(y%2==1){
		r*=x;
		r%=mod;
	}
	return r;
}
long long int minv(int x){
	return mpow(x,mod-2);
}
int main(){
	int i;
	long long int ans;
	scanf("%d%d",&n,&m);
	ans=0;
	for(i=m+2;i<=n+1;i++){
		ans+=minv(i)*(n+2-i);
		ans%=mod;
	}
	ans*=n+1;
	ans%=mod;
	for(i=1;i<=n;i++){
		ans*=i;
		ans%=mod;
	}
	printf("%lld",ans);
	return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 92 / 92