#include <cstdio>
#include <algorithm>
#define ll long long
#define mod 1000000007
ll n,k,res,now=1;
ll table[200010],stable[200010],sstable[200010];
int main(){
int i;
scanf("%lld %lld",&n,&k); table[0]=1; stable[0]=1; sstable[0]=k;
for(i=2;i<=2*n;i+=2){
table[i]=sstable[i-2]; stable[i]=stable[i-2]+table[i]; stable[i]%=mod; sstable[i]=sstable[i-2]*k+table[i]*k; sstable[i]%=mod;
}
for(i=0;i<=n;i++){
res+=table[n-i]*now; now*=k; res%=mod;
}
printf("%lld",res);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
0 ms |
5768 KB |
SIGSEGV Segmentation fault |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Halted |
0 ms |
0 KB |
- |