#include<stdio.h>
long long int n,m;
long long int dp[2001000];
long long int mod=1000000007;
long long int mpow(long long int x,long long 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(long long int x){
return mpow(x,mod-2);
}
int main(){
long long int i;
long long int cat;
scanf("%lld%lld",&n,&m);
dp[0]=1;
cat=1;
for(i=0;i<n;i++){
dp[i+1]=dp[i]*(m+1);
dp[i+1]%=mod;
if(i%2==0){
dp[i+1]+=mod-cat;
dp[i+1]%=mod;
cat*=i+1;
cat%=mod;
cat*=i+2;
cat%=mod;
cat*=minv(i/2+1);
cat%=mod;
cat*=minv(i/2+2);
cat%=mod;
cat*=m;
cat%=mod;
}
}
printf("%lld",dp[n]);
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
0 ms |
16716 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Halted |
0 ms |
0 KB |
- |