#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const LL MOD = 1000000007;
LL powmod(LL a, LL n){
if(n == 0) return 1;
if(n % 2) return (a * powmod(a, n-1)) % MOD;
LL c = powmod(a, n/2);
return (c * c) % MOD;
}
LL inv(LL a){
return powmod(a, MOD-2);
}
LL fact[110000];
LL invfact[110000];
int main(){
fact[0] = invfact[0] = 1;
for(LL i = 1; i < 110000; i++){
fact[i] = (i * fact[i-1]) % MOD;
invfact[i] = inv(fact[i]);
}
LL n, k;
cin >> n >> k;
k--;
LL ans = 0;
for(LL i = 0; i <= k; i++){
LL cur = powmod(k+1-i,n);
cur = (cur * fact[n+1]) % MOD;
cur = (cur * invfact[i]) % MOD;
cur = (cur * invfact[n+1-i]) % MOD;
if(i % 2) cur *= -1;
ans = (ans + cur) % MOD;
}
ans %= MOD;
if(ans < 0) ans += MOD;
cout << ans << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
41 ms |
2040 KB |
Output is correct |
2 |
Correct |
42 ms |
2152 KB |
Output is correct |
3 |
Correct |
40 ms |
2152 KB |
Output is correct |
4 |
Correct |
38 ms |
2152 KB |
Output is correct |
5 |
Correct |
42 ms |
2152 KB |
Output is correct |
6 |
Correct |
37 ms |
2184 KB |
Output is correct |
7 |
Correct |
38 ms |
2200 KB |
Output is correct |
8 |
Correct |
38 ms |
2260 KB |
Output is correct |
9 |
Correct |
38 ms |
2260 KB |
Output is correct |
10 |
Correct |
40 ms |
2260 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
41 ms |
2040 KB |
Output is correct |
2 |
Correct |
42 ms |
2152 KB |
Output is correct |
3 |
Correct |
40 ms |
2152 KB |
Output is correct |
4 |
Correct |
38 ms |
2152 KB |
Output is correct |
5 |
Correct |
42 ms |
2152 KB |
Output is correct |
6 |
Correct |
37 ms |
2184 KB |
Output is correct |
7 |
Correct |
38 ms |
2200 KB |
Output is correct |
8 |
Correct |
38 ms |
2260 KB |
Output is correct |
9 |
Correct |
38 ms |
2260 KB |
Output is correct |
10 |
Correct |
40 ms |
2260 KB |
Output is correct |
11 |
Correct |
40 ms |
2260 KB |
Output is correct |
12 |
Correct |
37 ms |
2260 KB |
Output is correct |
13 |
Correct |
39 ms |
2260 KB |
Output is correct |
14 |
Correct |
40 ms |
2260 KB |
Output is correct |
15 |
Correct |
38 ms |
2260 KB |
Output is correct |
16 |
Correct |
39 ms |
2260 KB |
Output is correct |
17 |
Correct |
39 ms |
2288 KB |
Output is correct |
18 |
Correct |
45 ms |
2288 KB |
Output is correct |
19 |
Correct |
46 ms |
2288 KB |
Output is correct |
20 |
Correct |
40 ms |
2288 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
41 ms |
2040 KB |
Output is correct |
2 |
Correct |
42 ms |
2152 KB |
Output is correct |
3 |
Correct |
40 ms |
2152 KB |
Output is correct |
4 |
Correct |
38 ms |
2152 KB |
Output is correct |
5 |
Correct |
42 ms |
2152 KB |
Output is correct |
6 |
Correct |
37 ms |
2184 KB |
Output is correct |
7 |
Correct |
38 ms |
2200 KB |
Output is correct |
8 |
Correct |
38 ms |
2260 KB |
Output is correct |
9 |
Correct |
38 ms |
2260 KB |
Output is correct |
10 |
Correct |
40 ms |
2260 KB |
Output is correct |
11 |
Correct |
40 ms |
2260 KB |
Output is correct |
12 |
Correct |
37 ms |
2260 KB |
Output is correct |
13 |
Correct |
39 ms |
2260 KB |
Output is correct |
14 |
Correct |
40 ms |
2260 KB |
Output is correct |
15 |
Correct |
38 ms |
2260 KB |
Output is correct |
16 |
Correct |
39 ms |
2260 KB |
Output is correct |
17 |
Correct |
39 ms |
2288 KB |
Output is correct |
18 |
Correct |
45 ms |
2288 KB |
Output is correct |
19 |
Correct |
46 ms |
2288 KB |
Output is correct |
20 |
Correct |
40 ms |
2288 KB |
Output is correct |
21 |
Correct |
39 ms |
2288 KB |
Output is correct |
22 |
Correct |
42 ms |
2288 KB |
Output is correct |
23 |
Correct |
45 ms |
2292 KB |
Output is correct |
24 |
Correct |
45 ms |
2292 KB |
Output is correct |
25 |
Correct |
41 ms |
2292 KB |
Output is correct |
26 |
Correct |
38 ms |
2292 KB |
Output is correct |
27 |
Correct |
42 ms |
2292 KB |
Output is correct |
28 |
Correct |
40 ms |
2388 KB |
Output is correct |
29 |
Correct |
41 ms |
2388 KB |
Output is correct |
30 |
Correct |
39 ms |
2388 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
41 ms |
2040 KB |
Output is correct |
2 |
Correct |
42 ms |
2152 KB |
Output is correct |
3 |
Correct |
40 ms |
2152 KB |
Output is correct |
4 |
Correct |
38 ms |
2152 KB |
Output is correct |
5 |
Correct |
42 ms |
2152 KB |
Output is correct |
6 |
Correct |
37 ms |
2184 KB |
Output is correct |
7 |
Correct |
38 ms |
2200 KB |
Output is correct |
8 |
Correct |
38 ms |
2260 KB |
Output is correct |
9 |
Correct |
38 ms |
2260 KB |
Output is correct |
10 |
Correct |
40 ms |
2260 KB |
Output is correct |
11 |
Correct |
40 ms |
2260 KB |
Output is correct |
12 |
Correct |
37 ms |
2260 KB |
Output is correct |
13 |
Correct |
39 ms |
2260 KB |
Output is correct |
14 |
Correct |
40 ms |
2260 KB |
Output is correct |
15 |
Correct |
38 ms |
2260 KB |
Output is correct |
16 |
Correct |
39 ms |
2260 KB |
Output is correct |
17 |
Correct |
39 ms |
2288 KB |
Output is correct |
18 |
Correct |
45 ms |
2288 KB |
Output is correct |
19 |
Correct |
46 ms |
2288 KB |
Output is correct |
20 |
Correct |
40 ms |
2288 KB |
Output is correct |
21 |
Correct |
39 ms |
2288 KB |
Output is correct |
22 |
Correct |
42 ms |
2288 KB |
Output is correct |
23 |
Correct |
45 ms |
2292 KB |
Output is correct |
24 |
Correct |
45 ms |
2292 KB |
Output is correct |
25 |
Correct |
41 ms |
2292 KB |
Output is correct |
26 |
Correct |
38 ms |
2292 KB |
Output is correct |
27 |
Correct |
42 ms |
2292 KB |
Output is correct |
28 |
Correct |
40 ms |
2388 KB |
Output is correct |
29 |
Correct |
41 ms |
2388 KB |
Output is correct |
30 |
Correct |
39 ms |
2388 KB |
Output is correct |
31 |
Correct |
38 ms |
2388 KB |
Output is correct |
32 |
Correct |
47 ms |
2388 KB |
Output is correct |
33 |
Correct |
42 ms |
2388 KB |
Output is correct |
34 |
Correct |
44 ms |
2388 KB |
Output is correct |
35 |
Correct |
56 ms |
2392 KB |
Output is correct |
36 |
Correct |
59 ms |
2396 KB |
Output is correct |
37 |
Correct |
60 ms |
2400 KB |
Output is correct |
38 |
Correct |
47 ms |
2448 KB |
Output is correct |
39 |
Correct |
44 ms |
2448 KB |
Output is correct |
40 |
Correct |
48 ms |
2448 KB |
Output is correct |