#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
const int mod = 1e9 + 7;
int fac[maxn], revfac[maxn];
ll power(ll a, ll b){
if (b == 0)
return 1;
ll ret = power(a, b / 2);
ret = 1ll * ret * ret % mod;
if (b & 1)
return ret * a % mod;
return ret;
}
ll C(int n, int r){
return 1ll * fac[n] * revfac[r] % mod * revfac[n - r] % mod;
}
int main(){
ios_base::sync_with_stdio(false);
int n, m;
cin >> n >> m;
m --;
fac[0] = 1;
for (int i = 1; i <= n + 5; i++)
fac[i] = 1ll * fac[i - 1] * i % mod;
revfac[n + 5] = power(fac[n + 5], mod - 2);
for (int i = n + 4; i >= 0; i--)
revfac[i] = 1ll * revfac[i + 1] * (i + 1) % mod;
ll answer = 0;
int sign = 1;
for (int k = 0; k <= m; k++){
ll t = 1ll * sign * C(n + 1, k) * power(m + 1 - k, n) % mod;
answer = (answer + t + mod) % mod;
sign *= -1;
}
cout << answer << endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
4 |
Correct |
2 ms |
384 KB |
Output is correct |
5 |
Correct |
2 ms |
384 KB |
Output is correct |
6 |
Correct |
2 ms |
384 KB |
Output is correct |
7 |
Correct |
2 ms |
384 KB |
Output is correct |
8 |
Correct |
2 ms |
384 KB |
Output is correct |
9 |
Correct |
2 ms |
384 KB |
Output is correct |
10 |
Correct |
2 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
4 |
Correct |
2 ms |
384 KB |
Output is correct |
5 |
Correct |
2 ms |
384 KB |
Output is correct |
6 |
Correct |
2 ms |
384 KB |
Output is correct |
7 |
Correct |
2 ms |
384 KB |
Output is correct |
8 |
Correct |
2 ms |
384 KB |
Output is correct |
9 |
Correct |
2 ms |
384 KB |
Output is correct |
10 |
Correct |
2 ms |
384 KB |
Output is correct |
11 |
Correct |
2 ms |
384 KB |
Output is correct |
12 |
Correct |
2 ms |
356 KB |
Output is correct |
13 |
Correct |
2 ms |
384 KB |
Output is correct |
14 |
Correct |
2 ms |
384 KB |
Output is correct |
15 |
Correct |
2 ms |
384 KB |
Output is correct |
16 |
Correct |
2 ms |
384 KB |
Output is correct |
17 |
Correct |
2 ms |
384 KB |
Output is correct |
18 |
Correct |
2 ms |
384 KB |
Output is correct |
19 |
Correct |
2 ms |
384 KB |
Output is correct |
20 |
Correct |
2 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
4 |
Correct |
2 ms |
384 KB |
Output is correct |
5 |
Correct |
2 ms |
384 KB |
Output is correct |
6 |
Correct |
2 ms |
384 KB |
Output is correct |
7 |
Correct |
2 ms |
384 KB |
Output is correct |
8 |
Correct |
2 ms |
384 KB |
Output is correct |
9 |
Correct |
2 ms |
384 KB |
Output is correct |
10 |
Correct |
2 ms |
384 KB |
Output is correct |
11 |
Correct |
2 ms |
384 KB |
Output is correct |
12 |
Correct |
2 ms |
356 KB |
Output is correct |
13 |
Correct |
2 ms |
384 KB |
Output is correct |
14 |
Correct |
2 ms |
384 KB |
Output is correct |
15 |
Correct |
2 ms |
384 KB |
Output is correct |
16 |
Correct |
2 ms |
384 KB |
Output is correct |
17 |
Correct |
2 ms |
384 KB |
Output is correct |
18 |
Correct |
2 ms |
384 KB |
Output is correct |
19 |
Correct |
2 ms |
384 KB |
Output is correct |
20 |
Correct |
2 ms |
384 KB |
Output is correct |
21 |
Correct |
2 ms |
384 KB |
Output is correct |
22 |
Correct |
2 ms |
384 KB |
Output is correct |
23 |
Correct |
2 ms |
300 KB |
Output is correct |
24 |
Correct |
2 ms |
384 KB |
Output is correct |
25 |
Correct |
2 ms |
384 KB |
Output is correct |
26 |
Correct |
2 ms |
356 KB |
Output is correct |
27 |
Correct |
2 ms |
384 KB |
Output is correct |
28 |
Correct |
2 ms |
384 KB |
Output is correct |
29 |
Correct |
2 ms |
384 KB |
Output is correct |
30 |
Correct |
2 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
4 |
Correct |
2 ms |
384 KB |
Output is correct |
5 |
Correct |
2 ms |
384 KB |
Output is correct |
6 |
Correct |
2 ms |
384 KB |
Output is correct |
7 |
Correct |
2 ms |
384 KB |
Output is correct |
8 |
Correct |
2 ms |
384 KB |
Output is correct |
9 |
Correct |
2 ms |
384 KB |
Output is correct |
10 |
Correct |
2 ms |
384 KB |
Output is correct |
11 |
Correct |
2 ms |
384 KB |
Output is correct |
12 |
Correct |
2 ms |
356 KB |
Output is correct |
13 |
Correct |
2 ms |
384 KB |
Output is correct |
14 |
Correct |
2 ms |
384 KB |
Output is correct |
15 |
Correct |
2 ms |
384 KB |
Output is correct |
16 |
Correct |
2 ms |
384 KB |
Output is correct |
17 |
Correct |
2 ms |
384 KB |
Output is correct |
18 |
Correct |
2 ms |
384 KB |
Output is correct |
19 |
Correct |
2 ms |
384 KB |
Output is correct |
20 |
Correct |
2 ms |
384 KB |
Output is correct |
21 |
Correct |
2 ms |
384 KB |
Output is correct |
22 |
Correct |
2 ms |
384 KB |
Output is correct |
23 |
Correct |
2 ms |
300 KB |
Output is correct |
24 |
Correct |
2 ms |
384 KB |
Output is correct |
25 |
Correct |
2 ms |
384 KB |
Output is correct |
26 |
Correct |
2 ms |
356 KB |
Output is correct |
27 |
Correct |
2 ms |
384 KB |
Output is correct |
28 |
Correct |
2 ms |
384 KB |
Output is correct |
29 |
Correct |
2 ms |
384 KB |
Output is correct |
30 |
Correct |
2 ms |
384 KB |
Output is correct |
31 |
Correct |
4 ms |
1152 KB |
Output is correct |
32 |
Correct |
5 ms |
1152 KB |
Output is correct |
33 |
Correct |
4 ms |
1152 KB |
Output is correct |
34 |
Correct |
7 ms |
1152 KB |
Output is correct |
35 |
Correct |
15 ms |
1152 KB |
Output is correct |
36 |
Correct |
17 ms |
1152 KB |
Output is correct |
37 |
Correct |
19 ms |
1152 KB |
Output is correct |
38 |
Correct |
4 ms |
512 KB |
Output is correct |
39 |
Correct |
9 ms |
896 KB |
Output is correct |
40 |
Correct |
10 ms |
1152 KB |
Output is correct |