#include <iostream>
#include <algorithm>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
const ll MAXN = 2077;
ll pw(ll a, ll m) {
if (!m)
return 1;
a %= MOD;
if (m % 2)
return a * pw(a, m - 1) % MOD;
return pw(a * a, m / 2);
}
ll fact[MAXN];
ll rfact[MAXN];
//ll choose(ll n, ll k) {
//if (n < 0 || k < 0 || k > n)
//return 0;
//return
//}
ll dp[MAXN][MAXN];
ll choose[MAXN][MAXN];
signed main() {
fact[0] = rfact[0] = 1;
for (int i = 1; i < MAXN; ++i) {
fact[i] = (fact[i - 1] * i) % MOD;
rfact[i] = pw(fact[i], MOD - 2);
}
for (int i = 0; i < MAXN; ++i) {
for (int j = 0; j <= i; ++j) {
choose[i][j] = (fact[i] * rfact[j] % MOD) * rfact[i - j] % MOD;
}
}
int n, m;
cin >> n >> m;
if (m == 1) {
cout << 0 << endl;
return 0;
}
int sz = 2 * n / m;
int szinc = 2 * n % m;
int smsz = sz + int(0 < szinc);
dp[0][0] = choose[n][smsz] * pw(2, n) % MOD;
for (int i = 0; i < m; ++i) {
dp[0][0] *= fact[sz + int(i < szinc)];
dp[0][0] %= MOD;
}
for (int i = 1; i < m; ++i) {
int szi = sz + int(i < szinc);
for (int c = 0; c <= n; ++c) {
for (int cp = max({0, smsz - n, c - szi}); cp <= c && smsz - cp * 2 >= 0; ++cp) {
ll cnt1 = smsz - cp * 2;
ll cnt0 = n + cp - smsz;
if (szi - c + cp < 0)
continue;
dp[i][c] += (dp[i - 1][cp] * choose[cnt1][c - cp] % MOD) * choose[cnt0][szi - (c - cp)];
dp[i][c] %= MOD;
}
//cout << dp[i][c] << ' ';
}
smsz += szi;
//cout << endl;
}
cout << dp[m - 1][n] % MOD << endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
24524 KB |
Output is correct |
2 |
Correct |
19 ms |
24524 KB |
Output is correct |
3 |
Correct |
15 ms |
24512 KB |
Output is correct |
4 |
Correct |
15 ms |
24540 KB |
Output is correct |
5 |
Correct |
16 ms |
24440 KB |
Output is correct |
6 |
Correct |
17 ms |
24440 KB |
Output is correct |
7 |
Correct |
16 ms |
24488 KB |
Output is correct |
8 |
Correct |
16 ms |
24452 KB |
Output is correct |
9 |
Correct |
16 ms |
24524 KB |
Output is correct |
10 |
Correct |
16 ms |
24500 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
24524 KB |
Output is correct |
2 |
Correct |
19 ms |
24524 KB |
Output is correct |
3 |
Correct |
15 ms |
24512 KB |
Output is correct |
4 |
Correct |
15 ms |
24540 KB |
Output is correct |
5 |
Correct |
16 ms |
24440 KB |
Output is correct |
6 |
Correct |
17 ms |
24440 KB |
Output is correct |
7 |
Correct |
16 ms |
24488 KB |
Output is correct |
8 |
Correct |
16 ms |
24452 KB |
Output is correct |
9 |
Correct |
16 ms |
24524 KB |
Output is correct |
10 |
Correct |
16 ms |
24500 KB |
Output is correct |
11 |
Correct |
19 ms |
24644 KB |
Output is correct |
12 |
Correct |
17 ms |
24780 KB |
Output is correct |
13 |
Correct |
16 ms |
24500 KB |
Output is correct |
14 |
Correct |
16 ms |
24600 KB |
Output is correct |
15 |
Correct |
16 ms |
24780 KB |
Output is correct |
16 |
Correct |
16 ms |
24560 KB |
Output is correct |
17 |
Correct |
16 ms |
24676 KB |
Output is correct |
18 |
Correct |
16 ms |
24668 KB |
Output is correct |
19 |
Correct |
15 ms |
24496 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
24524 KB |
Output is correct |
2 |
Correct |
19 ms |
24524 KB |
Output is correct |
3 |
Correct |
15 ms |
24512 KB |
Output is correct |
4 |
Correct |
15 ms |
24540 KB |
Output is correct |
5 |
Correct |
16 ms |
24440 KB |
Output is correct |
6 |
Correct |
17 ms |
24440 KB |
Output is correct |
7 |
Correct |
16 ms |
24488 KB |
Output is correct |
8 |
Correct |
16 ms |
24452 KB |
Output is correct |
9 |
Correct |
16 ms |
24524 KB |
Output is correct |
10 |
Correct |
16 ms |
24500 KB |
Output is correct |
11 |
Correct |
19 ms |
24644 KB |
Output is correct |
12 |
Correct |
17 ms |
24780 KB |
Output is correct |
13 |
Correct |
16 ms |
24500 KB |
Output is correct |
14 |
Correct |
16 ms |
24600 KB |
Output is correct |
15 |
Correct |
16 ms |
24780 KB |
Output is correct |
16 |
Correct |
16 ms |
24560 KB |
Output is correct |
17 |
Correct |
16 ms |
24676 KB |
Output is correct |
18 |
Correct |
16 ms |
24668 KB |
Output is correct |
19 |
Correct |
15 ms |
24496 KB |
Output is correct |
20 |
Correct |
16 ms |
24580 KB |
Output is correct |
21 |
Correct |
16 ms |
24800 KB |
Output is correct |
22 |
Correct |
17 ms |
25652 KB |
Output is correct |
23 |
Correct |
16 ms |
24524 KB |
Output is correct |
24 |
Correct |
16 ms |
25164 KB |
Output is correct |
25 |
Correct |
17 ms |
25548 KB |
Output is correct |
26 |
Correct |
16 ms |
24588 KB |
Output is correct |
27 |
Correct |
19 ms |
25884 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
24524 KB |
Output is correct |
2 |
Correct |
19 ms |
24524 KB |
Output is correct |
3 |
Correct |
15 ms |
24512 KB |
Output is correct |
4 |
Correct |
15 ms |
24540 KB |
Output is correct |
5 |
Correct |
16 ms |
24440 KB |
Output is correct |
6 |
Correct |
17 ms |
24440 KB |
Output is correct |
7 |
Correct |
16 ms |
24488 KB |
Output is correct |
8 |
Correct |
16 ms |
24452 KB |
Output is correct |
9 |
Correct |
16 ms |
24524 KB |
Output is correct |
10 |
Correct |
16 ms |
24500 KB |
Output is correct |
11 |
Correct |
19 ms |
24644 KB |
Output is correct |
12 |
Correct |
17 ms |
24780 KB |
Output is correct |
13 |
Correct |
16 ms |
24500 KB |
Output is correct |
14 |
Correct |
16 ms |
24600 KB |
Output is correct |
15 |
Correct |
16 ms |
24780 KB |
Output is correct |
16 |
Correct |
16 ms |
24560 KB |
Output is correct |
17 |
Correct |
16 ms |
24676 KB |
Output is correct |
18 |
Correct |
16 ms |
24668 KB |
Output is correct |
19 |
Correct |
15 ms |
24496 KB |
Output is correct |
20 |
Correct |
16 ms |
24580 KB |
Output is correct |
21 |
Correct |
16 ms |
24800 KB |
Output is correct |
22 |
Correct |
17 ms |
25652 KB |
Output is correct |
23 |
Correct |
16 ms |
24524 KB |
Output is correct |
24 |
Correct |
16 ms |
25164 KB |
Output is correct |
25 |
Correct |
17 ms |
25548 KB |
Output is correct |
26 |
Correct |
16 ms |
24588 KB |
Output is correct |
27 |
Correct |
19 ms |
25884 KB |
Output is correct |
28 |
Correct |
18 ms |
24588 KB |
Output is correct |
29 |
Correct |
18 ms |
26160 KB |
Output is correct |
30 |
Correct |
20 ms |
27568 KB |
Output is correct |
31 |
Correct |
18 ms |
24488 KB |
Output is correct |
32 |
Correct |
19 ms |
26312 KB |
Output is correct |
33 |
Correct |
21 ms |
27980 KB |
Output is correct |
34 |
Correct |
23 ms |
29692 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
24524 KB |
Output is correct |
2 |
Correct |
19 ms |
24524 KB |
Output is correct |
3 |
Correct |
15 ms |
24512 KB |
Output is correct |
4 |
Correct |
15 ms |
24540 KB |
Output is correct |
5 |
Correct |
16 ms |
24440 KB |
Output is correct |
6 |
Correct |
17 ms |
24440 KB |
Output is correct |
7 |
Correct |
16 ms |
24488 KB |
Output is correct |
8 |
Correct |
16 ms |
24452 KB |
Output is correct |
9 |
Correct |
16 ms |
24524 KB |
Output is correct |
10 |
Correct |
16 ms |
24500 KB |
Output is correct |
11 |
Correct |
19 ms |
24644 KB |
Output is correct |
12 |
Correct |
17 ms |
24780 KB |
Output is correct |
13 |
Correct |
16 ms |
24500 KB |
Output is correct |
14 |
Correct |
16 ms |
24600 KB |
Output is correct |
15 |
Correct |
16 ms |
24780 KB |
Output is correct |
16 |
Correct |
16 ms |
24560 KB |
Output is correct |
17 |
Correct |
16 ms |
24676 KB |
Output is correct |
18 |
Correct |
16 ms |
24668 KB |
Output is correct |
19 |
Correct |
15 ms |
24496 KB |
Output is correct |
20 |
Correct |
16 ms |
24580 KB |
Output is correct |
21 |
Correct |
16 ms |
24800 KB |
Output is correct |
22 |
Correct |
17 ms |
25652 KB |
Output is correct |
23 |
Correct |
16 ms |
24524 KB |
Output is correct |
24 |
Correct |
16 ms |
25164 KB |
Output is correct |
25 |
Correct |
17 ms |
25548 KB |
Output is correct |
26 |
Correct |
16 ms |
24588 KB |
Output is correct |
27 |
Correct |
19 ms |
25884 KB |
Output is correct |
28 |
Correct |
18 ms |
24588 KB |
Output is correct |
29 |
Correct |
18 ms |
26160 KB |
Output is correct |
30 |
Correct |
20 ms |
27568 KB |
Output is correct |
31 |
Correct |
18 ms |
24488 KB |
Output is correct |
32 |
Correct |
19 ms |
26312 KB |
Output is correct |
33 |
Correct |
21 ms |
27980 KB |
Output is correct |
34 |
Correct |
23 ms |
29692 KB |
Output is correct |
35 |
Correct |
27 ms |
24620 KB |
Output is correct |
36 |
Correct |
42 ms |
37324 KB |
Output is correct |
37 |
Correct |
28 ms |
24644 KB |
Output is correct |
38 |
Correct |
32 ms |
30404 KB |
Output is correct |
39 |
Correct |
37 ms |
35348 KB |
Output is correct |
40 |
Correct |
50 ms |
40376 KB |
Output is correct |