#include<bits/stdc++.h>
using namespace std;
const long long maxn=100000+10;
long long mod=1e9+7;
long long fact[maxn],revfact[maxn];
long long mypow(long long m,long long y){
if(y==0){
return 1;
}
long long p=mypow(m,(y>>1));
p*=p;
p%=mod;
if(y&1){
p*=m;
p%=mod;
}
return p;
}
void aval(){
fact[0]=1;
for(long long i=1;i<maxn;i++){
fact[i]=1ll*fact[i-1]*i%mod;
}
revfact[maxn-1]=mypow(fact[maxn-1],mod-2);
for(long long i=maxn-2;i>=0;i--){
revfact[i]=1ll*revfact[i+1]*(i+1)%mod;
}
}
long long c(long long i,long long j){
if(i<0||j<0||i<j){
return 0;
}
return 1ll*fact[i]*revfact[j]%mod*revfact[i-j]%mod;
}
int main(){
aval();
long long n,k;
cin>>n>>k;
long long res=0;
for(long long i=k;i>=1;i--){
long long fake=mypow(i,n)*c(n+1,k-i)%mod;
if((k-i)&1){
res-=fake;
}
else{
res+=fake;
}
//cout<<i<<" "<<fake<<" "<<mypow(i,n)<<" "<<c(n+1,k-i)<<endl;
}
// cout<<res<<endl;
res+=1000000*mod;
res%=mod;
// res=abs(res);
// res%=mod;
// res = ((res % mod) + mod) % mod;
cout<<res<<"\n";
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1884 KB |
Output is correct |
2 |
Correct |
3 ms |
1884 KB |
Output is correct |
3 |
Correct |
3 ms |
1880 KB |
Output is correct |
4 |
Correct |
3 ms |
1884 KB |
Output is correct |
5 |
Correct |
3 ms |
1884 KB |
Output is correct |
6 |
Correct |
3 ms |
1884 KB |
Output is correct |
7 |
Correct |
3 ms |
1884 KB |
Output is correct |
8 |
Correct |
3 ms |
1884 KB |
Output is correct |
9 |
Correct |
3 ms |
1880 KB |
Output is correct |
10 |
Correct |
3 ms |
1880 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1884 KB |
Output is correct |
2 |
Correct |
3 ms |
1884 KB |
Output is correct |
3 |
Correct |
3 ms |
1880 KB |
Output is correct |
4 |
Correct |
3 ms |
1884 KB |
Output is correct |
5 |
Correct |
3 ms |
1884 KB |
Output is correct |
6 |
Correct |
3 ms |
1884 KB |
Output is correct |
7 |
Correct |
3 ms |
1884 KB |
Output is correct |
8 |
Correct |
3 ms |
1884 KB |
Output is correct |
9 |
Correct |
3 ms |
1880 KB |
Output is correct |
10 |
Correct |
3 ms |
1880 KB |
Output is correct |
11 |
Correct |
3 ms |
1884 KB |
Output is correct |
12 |
Correct |
3 ms |
1884 KB |
Output is correct |
13 |
Correct |
3 ms |
1816 KB |
Output is correct |
14 |
Correct |
3 ms |
1880 KB |
Output is correct |
15 |
Correct |
3 ms |
1884 KB |
Output is correct |
16 |
Correct |
3 ms |
1884 KB |
Output is correct |
17 |
Correct |
3 ms |
1884 KB |
Output is correct |
18 |
Correct |
4 ms |
1884 KB |
Output is correct |
19 |
Correct |
3 ms |
1884 KB |
Output is correct |
20 |
Correct |
3 ms |
1884 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1884 KB |
Output is correct |
2 |
Correct |
3 ms |
1884 KB |
Output is correct |
3 |
Correct |
3 ms |
1880 KB |
Output is correct |
4 |
Correct |
3 ms |
1884 KB |
Output is correct |
5 |
Correct |
3 ms |
1884 KB |
Output is correct |
6 |
Correct |
3 ms |
1884 KB |
Output is correct |
7 |
Correct |
3 ms |
1884 KB |
Output is correct |
8 |
Correct |
3 ms |
1884 KB |
Output is correct |
9 |
Correct |
3 ms |
1880 KB |
Output is correct |
10 |
Correct |
3 ms |
1880 KB |
Output is correct |
11 |
Correct |
3 ms |
1884 KB |
Output is correct |
12 |
Correct |
3 ms |
1884 KB |
Output is correct |
13 |
Correct |
3 ms |
1816 KB |
Output is correct |
14 |
Correct |
3 ms |
1880 KB |
Output is correct |
15 |
Correct |
3 ms |
1884 KB |
Output is correct |
16 |
Correct |
3 ms |
1884 KB |
Output is correct |
17 |
Correct |
3 ms |
1884 KB |
Output is correct |
18 |
Correct |
4 ms |
1884 KB |
Output is correct |
19 |
Correct |
3 ms |
1884 KB |
Output is correct |
20 |
Correct |
3 ms |
1884 KB |
Output is correct |
21 |
Correct |
3 ms |
2140 KB |
Output is correct |
22 |
Correct |
3 ms |
2140 KB |
Output is correct |
23 |
Correct |
3 ms |
1884 KB |
Output is correct |
24 |
Correct |
3 ms |
2140 KB |
Output is correct |
25 |
Correct |
3 ms |
2004 KB |
Output is correct |
26 |
Correct |
3 ms |
1880 KB |
Output is correct |
27 |
Correct |
3 ms |
2000 KB |
Output is correct |
28 |
Correct |
4 ms |
1884 KB |
Output is correct |
29 |
Correct |
3 ms |
1884 KB |
Output is correct |
30 |
Correct |
3 ms |
1884 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1884 KB |
Output is correct |
2 |
Correct |
3 ms |
1884 KB |
Output is correct |
3 |
Correct |
3 ms |
1880 KB |
Output is correct |
4 |
Correct |
3 ms |
1884 KB |
Output is correct |
5 |
Correct |
3 ms |
1884 KB |
Output is correct |
6 |
Correct |
3 ms |
1884 KB |
Output is correct |
7 |
Correct |
3 ms |
1884 KB |
Output is correct |
8 |
Correct |
3 ms |
1884 KB |
Output is correct |
9 |
Correct |
3 ms |
1880 KB |
Output is correct |
10 |
Correct |
3 ms |
1880 KB |
Output is correct |
11 |
Correct |
3 ms |
1884 KB |
Output is correct |
12 |
Correct |
3 ms |
1884 KB |
Output is correct |
13 |
Correct |
3 ms |
1816 KB |
Output is correct |
14 |
Correct |
3 ms |
1880 KB |
Output is correct |
15 |
Correct |
3 ms |
1884 KB |
Output is correct |
16 |
Correct |
3 ms |
1884 KB |
Output is correct |
17 |
Correct |
3 ms |
1884 KB |
Output is correct |
18 |
Correct |
4 ms |
1884 KB |
Output is correct |
19 |
Correct |
3 ms |
1884 KB |
Output is correct |
20 |
Correct |
3 ms |
1884 KB |
Output is correct |
21 |
Correct |
3 ms |
2140 KB |
Output is correct |
22 |
Correct |
3 ms |
2140 KB |
Output is correct |
23 |
Correct |
3 ms |
1884 KB |
Output is correct |
24 |
Correct |
3 ms |
2140 KB |
Output is correct |
25 |
Correct |
3 ms |
2004 KB |
Output is correct |
26 |
Correct |
3 ms |
1880 KB |
Output is correct |
27 |
Correct |
3 ms |
2000 KB |
Output is correct |
28 |
Correct |
4 ms |
1884 KB |
Output is correct |
29 |
Correct |
3 ms |
1884 KB |
Output is correct |
30 |
Correct |
3 ms |
1884 KB |
Output is correct |
31 |
Correct |
3 ms |
1884 KB |
Output is correct |
32 |
Correct |
3 ms |
1980 KB |
Output is correct |
33 |
Correct |
4 ms |
1884 KB |
Output is correct |
34 |
Correct |
6 ms |
1900 KB |
Output is correct |
35 |
Correct |
19 ms |
1888 KB |
Output is correct |
36 |
Correct |
21 ms |
1884 KB |
Output is correct |
37 |
Correct |
23 ms |
1884 KB |
Output is correct |
38 |
Correct |
6 ms |
1884 KB |
Output is correct |
39 |
Correct |
9 ms |
1884 KB |
Output is correct |
40 |
Correct |
12 ms |
2140 KB |
Output is correct |