#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(),v.end()
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }
const int N = 2e3 + 7;
const int Mod = 1e9 + 7;
const int INF = 1e9 + 7;
const ll BASE = 137;
int n, m;
int h[N];
int dp[N][2 * N];
int fac[2 * N], C[2 * N][2 * N];
int pre[N];
inline void add (int &A, int B) { A += B; if (A > Mod) A -= Mod; }
void solution () {
cin >> n >> m;
fac[0] = 1;
rep (i, 1, 2 * n) fac[i] = 1LL * fac[i - 1] * i % Mod;
rep (i, 0, 2 * n)
rep (j, 0, i) {
if (j == 0 || j == i) C[j][i] = 1;
else C[j][i] = C[j][i - 1] + C[j - 1][i - 1];
if (C[j][i] > Mod) C[j][i] -= Mod;
}
// cout << C[8][23] <<"\n";
rep (i, 0, 2 * n - 1) {
h[i % m + 1]++;
}
// vector<pair<int,int>> vec;
// rep (j, 0, 1)
// rep (i, 1, n) vec.push_back({i, j});
// sort (ALL(vec));
// ll res = 0;
// do {
// int ok = 1;
// rep (i, 0, 2 * n - 1) if (i >= m && vec[i].fs == vec[i - m].fs) ok = 0;
// res += ok;
// if (ok) {
// iter (&id, vec) cout << id.fs<<","<<id.se <<" ";
// cout<<"\n";
// }
// }while(next_permutation(ALL(vec)));
// cout << res <<"\n";
rep (i, 1, m) {
pre[i] = pre[i - 1] + h[i];
}
dp[0][0] = 1;
rep (i, 0, m)
rep (j, 0, pre[i]) {
int pw2 = 1;
rep (x, 0, h[i + 1]) {
int nj = j + 2 * x - h[i + 1];
if (nj >= 0 && nj <= 2 * n) {
int pcol = nj + ((pre[i + 1] - nj) >> 1);
int remcol = n - (pcol - x);
if (remcol >= 0)
add (dp[i + 1][nj], 1LL * dp[i][j] * C[h[i + 1] - x][j] % Mod * C[x][h[i + 1]] % Mod * C[x][remcol] % Mod * fac[x] % Mod * fac[h[i + 1] - x] % Mod * pw2 % Mod);
}
pw2 = 1LL * pw2 * 2 % Mod;
}
// cout << i<<","<<j<<" "<<dp[i][j] <<"\n";
}
cout << dp[m][0] <<"\n";
}
#define file(name) freopen(name".inp","r",stdin); \
freopen(name".out","w",stdout);
int main () {
// file("c");
ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
no bug challenge +2
2 + 8 * 2 - 9
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
0 ms |
2396 KB |
Output is correct |
3 |
Correct |
0 ms |
2396 KB |
Output is correct |
4 |
Correct |
0 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
0 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
0 ms |
2396 KB |
Output is correct |
3 |
Correct |
0 ms |
2396 KB |
Output is correct |
4 |
Correct |
0 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
0 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
11 |
Correct |
1 ms |
6488 KB |
Output is correct |
12 |
Correct |
1 ms |
4444 KB |
Output is correct |
13 |
Correct |
0 ms |
4444 KB |
Output is correct |
14 |
Correct |
1 ms |
4444 KB |
Output is correct |
15 |
Correct |
1 ms |
6748 KB |
Output is correct |
16 |
Correct |
1 ms |
6492 KB |
Output is correct |
17 |
Correct |
0 ms |
4444 KB |
Output is correct |
18 |
Correct |
1 ms |
4444 KB |
Output is correct |
19 |
Correct |
1 ms |
6492 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
0 ms |
2396 KB |
Output is correct |
3 |
Correct |
0 ms |
2396 KB |
Output is correct |
4 |
Correct |
0 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
0 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
11 |
Correct |
1 ms |
6488 KB |
Output is correct |
12 |
Correct |
1 ms |
4444 KB |
Output is correct |
13 |
Correct |
0 ms |
4444 KB |
Output is correct |
14 |
Correct |
1 ms |
4444 KB |
Output is correct |
15 |
Correct |
1 ms |
6748 KB |
Output is correct |
16 |
Correct |
1 ms |
6492 KB |
Output is correct |
17 |
Correct |
0 ms |
4444 KB |
Output is correct |
18 |
Correct |
1 ms |
4444 KB |
Output is correct |
19 |
Correct |
1 ms |
6492 KB |
Output is correct |
20 |
Correct |
1 ms |
8540 KB |
Output is correct |
21 |
Correct |
1 ms |
8796 KB |
Output is correct |
22 |
Correct |
3 ms |
11752 KB |
Output is correct |
23 |
Correct |
2 ms |
10588 KB |
Output is correct |
24 |
Correct |
3 ms |
13160 KB |
Output is correct |
25 |
Correct |
3 ms |
11612 KB |
Output is correct |
26 |
Correct |
2 ms |
10588 KB |
Output is correct |
27 |
Correct |
4 ms |
13916 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
0 ms |
2396 KB |
Output is correct |
3 |
Correct |
0 ms |
2396 KB |
Output is correct |
4 |
Correct |
0 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
0 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
11 |
Correct |
1 ms |
6488 KB |
Output is correct |
12 |
Correct |
1 ms |
4444 KB |
Output is correct |
13 |
Correct |
0 ms |
4444 KB |
Output is correct |
14 |
Correct |
1 ms |
4444 KB |
Output is correct |
15 |
Correct |
1 ms |
6748 KB |
Output is correct |
16 |
Correct |
1 ms |
6492 KB |
Output is correct |
17 |
Correct |
0 ms |
4444 KB |
Output is correct |
18 |
Correct |
1 ms |
4444 KB |
Output is correct |
19 |
Correct |
1 ms |
6492 KB |
Output is correct |
20 |
Correct |
1 ms |
8540 KB |
Output is correct |
21 |
Correct |
1 ms |
8796 KB |
Output is correct |
22 |
Correct |
3 ms |
11752 KB |
Output is correct |
23 |
Correct |
2 ms |
10588 KB |
Output is correct |
24 |
Correct |
3 ms |
13160 KB |
Output is correct |
25 |
Correct |
3 ms |
11612 KB |
Output is correct |
26 |
Correct |
2 ms |
10588 KB |
Output is correct |
27 |
Correct |
4 ms |
13916 KB |
Output is correct |
28 |
Correct |
14 ms |
23640 KB |
Output is correct |
29 |
Correct |
17 ms |
24496 KB |
Output is correct |
30 |
Correct |
16 ms |
25948 KB |
Output is correct |
31 |
Correct |
12 ms |
23132 KB |
Output is correct |
32 |
Correct |
15 ms |
26716 KB |
Output is correct |
33 |
Correct |
19 ms |
28536 KB |
Output is correct |
34 |
Correct |
30 ms |
36176 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
0 ms |
2396 KB |
Output is correct |
3 |
Correct |
0 ms |
2396 KB |
Output is correct |
4 |
Correct |
0 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
0 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
11 |
Correct |
1 ms |
6488 KB |
Output is correct |
12 |
Correct |
1 ms |
4444 KB |
Output is correct |
13 |
Correct |
0 ms |
4444 KB |
Output is correct |
14 |
Correct |
1 ms |
4444 KB |
Output is correct |
15 |
Correct |
1 ms |
6748 KB |
Output is correct |
16 |
Correct |
1 ms |
6492 KB |
Output is correct |
17 |
Correct |
0 ms |
4444 KB |
Output is correct |
18 |
Correct |
1 ms |
4444 KB |
Output is correct |
19 |
Correct |
1 ms |
6492 KB |
Output is correct |
20 |
Correct |
1 ms |
8540 KB |
Output is correct |
21 |
Correct |
1 ms |
8796 KB |
Output is correct |
22 |
Correct |
3 ms |
11752 KB |
Output is correct |
23 |
Correct |
2 ms |
10588 KB |
Output is correct |
24 |
Correct |
3 ms |
13160 KB |
Output is correct |
25 |
Correct |
3 ms |
11612 KB |
Output is correct |
26 |
Correct |
2 ms |
10588 KB |
Output is correct |
27 |
Correct |
4 ms |
13916 KB |
Output is correct |
28 |
Correct |
14 ms |
23640 KB |
Output is correct |
29 |
Correct |
17 ms |
24496 KB |
Output is correct |
30 |
Correct |
16 ms |
25948 KB |
Output is correct |
31 |
Correct |
12 ms |
23132 KB |
Output is correct |
32 |
Correct |
15 ms |
26716 KB |
Output is correct |
33 |
Correct |
19 ms |
28536 KB |
Output is correct |
34 |
Correct |
30 ms |
36176 KB |
Output is correct |
35 |
Correct |
67 ms |
53976 KB |
Output is correct |
36 |
Correct |
109 ms |
72864 KB |
Output is correct |
37 |
Correct |
65 ms |
53976 KB |
Output is correct |
38 |
Correct |
80 ms |
61620 KB |
Output is correct |
39 |
Correct |
86 ms |
64540 KB |
Output is correct |
40 |
Correct |
140 ms |
79908 KB |
Output is correct |