#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define ar array
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
const int mod = 1e9 + 7, maxn = 1e5 + 5;
int fact[maxn], ifact[maxn];
int N, K;
int power(int a, int b) {
if (b == 0) return 1;
int res = power(a, b / 2);
if (b & 1) return (ll)res * res % mod * a % mod;
return (ll)res * res % mod;
}
int inv(int a) {
return power(a, mod - 2);
}
int binom(int k, int n) {
if (k < 0 || n < 0 || k > n) return 0;
return (ll)fact[n] * ifact[k] % mod * ifact[n - k] % mod;
}
void add(int & x, int y) {
x += y;
if (x >= mod) x -= mod;
if (x < 0) x += mod;
}
signed main(void) {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("A.INP", "r", stdin);
freopen("A.OUT", "w", stdout);
#endif // LOCAL
fact[0] = 1;
for (int i = 1; i < maxn; ++i) {
fact[i] = (ll)fact[i - 1] * i % mod;
}
ifact[maxn - 1] = inv(fact[maxn - 1]);
for (int i = maxn - 2; i >= 0; --i) {
ifact[i] = (ll)ifact[i + 1] * (i + 1) % mod;
}
cin >> N >> K;
int res = 0;
for (int i = 0; i <= K; ++i) {
int sign = 1;
if (i & 1) sign = -1;
int way = (ll)power(K - i, N) * binom(i, N + 1) % mod;
///cerr << way << '\n';
add(res, sign * way);
}
cout << res;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1152 KB |
Output is correct |
2 |
Correct |
2 ms |
1152 KB |
Output is correct |
3 |
Correct |
2 ms |
1152 KB |
Output is correct |
4 |
Correct |
2 ms |
1152 KB |
Output is correct |
5 |
Correct |
3 ms |
1152 KB |
Output is correct |
6 |
Correct |
2 ms |
1152 KB |
Output is correct |
7 |
Correct |
2 ms |
1152 KB |
Output is correct |
8 |
Correct |
3 ms |
1152 KB |
Output is correct |
9 |
Correct |
2 ms |
1152 KB |
Output is correct |
10 |
Correct |
3 ms |
1152 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1152 KB |
Output is correct |
2 |
Correct |
2 ms |
1152 KB |
Output is correct |
3 |
Correct |
2 ms |
1152 KB |
Output is correct |
4 |
Correct |
2 ms |
1152 KB |
Output is correct |
5 |
Correct |
3 ms |
1152 KB |
Output is correct |
6 |
Correct |
2 ms |
1152 KB |
Output is correct |
7 |
Correct |
2 ms |
1152 KB |
Output is correct |
8 |
Correct |
3 ms |
1152 KB |
Output is correct |
9 |
Correct |
2 ms |
1152 KB |
Output is correct |
10 |
Correct |
3 ms |
1152 KB |
Output is correct |
11 |
Correct |
3 ms |
1152 KB |
Output is correct |
12 |
Correct |
2 ms |
1152 KB |
Output is correct |
13 |
Correct |
2 ms |
1152 KB |
Output is correct |
14 |
Correct |
3 ms |
1152 KB |
Output is correct |
15 |
Correct |
3 ms |
1152 KB |
Output is correct |
16 |
Correct |
3 ms |
1152 KB |
Output is correct |
17 |
Correct |
2 ms |
1152 KB |
Output is correct |
18 |
Correct |
3 ms |
1056 KB |
Output is correct |
19 |
Correct |
3 ms |
1152 KB |
Output is correct |
20 |
Correct |
3 ms |
1152 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1152 KB |
Output is correct |
2 |
Correct |
2 ms |
1152 KB |
Output is correct |
3 |
Correct |
2 ms |
1152 KB |
Output is correct |
4 |
Correct |
2 ms |
1152 KB |
Output is correct |
5 |
Correct |
3 ms |
1152 KB |
Output is correct |
6 |
Correct |
2 ms |
1152 KB |
Output is correct |
7 |
Correct |
2 ms |
1152 KB |
Output is correct |
8 |
Correct |
3 ms |
1152 KB |
Output is correct |
9 |
Correct |
2 ms |
1152 KB |
Output is correct |
10 |
Correct |
3 ms |
1152 KB |
Output is correct |
11 |
Correct |
3 ms |
1152 KB |
Output is correct |
12 |
Correct |
2 ms |
1152 KB |
Output is correct |
13 |
Correct |
2 ms |
1152 KB |
Output is correct |
14 |
Correct |
3 ms |
1152 KB |
Output is correct |
15 |
Correct |
3 ms |
1152 KB |
Output is correct |
16 |
Correct |
3 ms |
1152 KB |
Output is correct |
17 |
Correct |
2 ms |
1152 KB |
Output is correct |
18 |
Correct |
3 ms |
1056 KB |
Output is correct |
19 |
Correct |
3 ms |
1152 KB |
Output is correct |
20 |
Correct |
3 ms |
1152 KB |
Output is correct |
21 |
Correct |
3 ms |
1152 KB |
Output is correct |
22 |
Correct |
3 ms |
1152 KB |
Output is correct |
23 |
Correct |
3 ms |
1152 KB |
Output is correct |
24 |
Correct |
3 ms |
1152 KB |
Output is correct |
25 |
Correct |
3 ms |
1152 KB |
Output is correct |
26 |
Correct |
3 ms |
1152 KB |
Output is correct |
27 |
Correct |
3 ms |
1152 KB |
Output is correct |
28 |
Correct |
3 ms |
1152 KB |
Output is correct |
29 |
Correct |
2 ms |
1152 KB |
Output is correct |
30 |
Correct |
3 ms |
1152 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1152 KB |
Output is correct |
2 |
Correct |
2 ms |
1152 KB |
Output is correct |
3 |
Correct |
2 ms |
1152 KB |
Output is correct |
4 |
Correct |
2 ms |
1152 KB |
Output is correct |
5 |
Correct |
3 ms |
1152 KB |
Output is correct |
6 |
Correct |
2 ms |
1152 KB |
Output is correct |
7 |
Correct |
2 ms |
1152 KB |
Output is correct |
8 |
Correct |
3 ms |
1152 KB |
Output is correct |
9 |
Correct |
2 ms |
1152 KB |
Output is correct |
10 |
Correct |
3 ms |
1152 KB |
Output is correct |
11 |
Correct |
3 ms |
1152 KB |
Output is correct |
12 |
Correct |
2 ms |
1152 KB |
Output is correct |
13 |
Correct |
2 ms |
1152 KB |
Output is correct |
14 |
Correct |
3 ms |
1152 KB |
Output is correct |
15 |
Correct |
3 ms |
1152 KB |
Output is correct |
16 |
Correct |
3 ms |
1152 KB |
Output is correct |
17 |
Correct |
2 ms |
1152 KB |
Output is correct |
18 |
Correct |
3 ms |
1056 KB |
Output is correct |
19 |
Correct |
3 ms |
1152 KB |
Output is correct |
20 |
Correct |
3 ms |
1152 KB |
Output is correct |
21 |
Correct |
3 ms |
1152 KB |
Output is correct |
22 |
Correct |
3 ms |
1152 KB |
Output is correct |
23 |
Correct |
3 ms |
1152 KB |
Output is correct |
24 |
Correct |
3 ms |
1152 KB |
Output is correct |
25 |
Correct |
3 ms |
1152 KB |
Output is correct |
26 |
Correct |
3 ms |
1152 KB |
Output is correct |
27 |
Correct |
3 ms |
1152 KB |
Output is correct |
28 |
Correct |
3 ms |
1152 KB |
Output is correct |
29 |
Correct |
2 ms |
1152 KB |
Output is correct |
30 |
Correct |
3 ms |
1152 KB |
Output is correct |
31 |
Correct |
3 ms |
1152 KB |
Output is correct |
32 |
Correct |
2 ms |
1152 KB |
Output is correct |
33 |
Correct |
3 ms |
1152 KB |
Output is correct |
34 |
Correct |
5 ms |
1152 KB |
Output is correct |
35 |
Correct |
18 ms |
1152 KB |
Output is correct |
36 |
Correct |
19 ms |
1152 KB |
Output is correct |
37 |
Correct |
21 ms |
1152 KB |
Output is correct |
38 |
Correct |
5 ms |
1056 KB |
Output is correct |
39 |
Correct |
8 ms |
1152 KB |
Output is correct |
40 |
Correct |
10 ms |
1152 KB |
Output is correct |