#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#define pb push_back
#define F first
#define S second
#define ld long double
#define all(a) a.begin(),a.end()
#define pii pair <int,int>
#define int long long
#define PII pair<pii , pii>
#define sz(v) (int)v.size()
#define rep(i , a , b) for(int i=a;i <= (b);i++)
#define per(i , a , b) for(int i=a;i >= (b);i--)
#define deb(x) cout <<#x << " : " << x << "\n" ;
using namespace std ;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 4000+10 + 10, inf = 1e9+10 , mod = 1e9 + 7 ;
int f[maxn], inv[maxn] , dp[maxn][maxn] ;
int po(int a, int b){
if(b==0)return 1 ;
int v =po(a,b/2) ;
v = v*v % mod ;
if(b&1) v= v*a % mod ;
return v ;
}
int c(int n , int k){
if(n < k || k < 0)return 0 ;
return f[n]*inv[k]%mod*inv[n-k]%mod ;
}
int t[maxn] ;
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
f[0] = 1;
rep(i , 1,maxn-1)f[i] = f[i-1] *i % mod ;
inv[maxn-1] = po(f[maxn-1] , mod-2) ;
per(i , maxn-2 ,0){
inv[i] = inv[i+1] * (i+1) % mod ;
}
int n , m;
cin >> n >> m ;
rep(i , 1, 2*n){
t[(i-1)%m]++;
}
dp[0][0] = 1;
rep(i , 1 ,m){
rep(j ,0 ,n){
rep(k , 0 , min(t[i-1] , j)){
dp[i][j-k+(t[i-1] - k)] = (dp[i][j-k+(t[i-1]-k)] + dp[i-1][j] * c(t[i-1] , k)%mod * f[k]%mod * c(j , k)%mod)%mod ;
}
}
}
int ans = dp[m][0] * po(2,n)%mod *f[n]%mod;
cout << ans<< "\n";
return 0 ;
}
/*
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
1 ms |
604 KB |
Output is correct |
12 |
Correct |
1 ms |
604 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
604 KB |
Output is correct |
16 |
Correct |
1 ms |
348 KB |
Output is correct |
17 |
Correct |
1 ms |
604 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
1 ms |
604 KB |
Output is correct |
12 |
Correct |
1 ms |
604 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
604 KB |
Output is correct |
16 |
Correct |
1 ms |
348 KB |
Output is correct |
17 |
Correct |
1 ms |
604 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
348 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
21 |
Correct |
1 ms |
860 KB |
Output is correct |
22 |
Correct |
4 ms |
2068 KB |
Output is correct |
23 |
Correct |
2 ms |
848 KB |
Output is correct |
24 |
Correct |
4 ms |
1372 KB |
Output is correct |
25 |
Correct |
4 ms |
1884 KB |
Output is correct |
26 |
Correct |
2 ms |
604 KB |
Output is correct |
27 |
Correct |
5 ms |
2392 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
1 ms |
604 KB |
Output is correct |
12 |
Correct |
1 ms |
604 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
604 KB |
Output is correct |
16 |
Correct |
1 ms |
348 KB |
Output is correct |
17 |
Correct |
1 ms |
604 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
348 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
21 |
Correct |
1 ms |
860 KB |
Output is correct |
22 |
Correct |
4 ms |
2068 KB |
Output is correct |
23 |
Correct |
2 ms |
848 KB |
Output is correct |
24 |
Correct |
4 ms |
1372 KB |
Output is correct |
25 |
Correct |
4 ms |
1884 KB |
Output is correct |
26 |
Correct |
2 ms |
604 KB |
Output is correct |
27 |
Correct |
5 ms |
2392 KB |
Output is correct |
28 |
Correct |
13 ms |
604 KB |
Output is correct |
29 |
Correct |
17 ms |
3524 KB |
Output is correct |
30 |
Correct |
19 ms |
5716 KB |
Output is correct |
31 |
Correct |
11 ms |
604 KB |
Output is correct |
32 |
Correct |
19 ms |
3700 KB |
Output is correct |
33 |
Correct |
23 ms |
6748 KB |
Output is correct |
34 |
Correct |
37 ms |
10332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
1 ms |
604 KB |
Output is correct |
12 |
Correct |
1 ms |
604 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
604 KB |
Output is correct |
16 |
Correct |
1 ms |
348 KB |
Output is correct |
17 |
Correct |
1 ms |
604 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
348 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
21 |
Correct |
1 ms |
860 KB |
Output is correct |
22 |
Correct |
4 ms |
2068 KB |
Output is correct |
23 |
Correct |
2 ms |
848 KB |
Output is correct |
24 |
Correct |
4 ms |
1372 KB |
Output is correct |
25 |
Correct |
4 ms |
1884 KB |
Output is correct |
26 |
Correct |
2 ms |
604 KB |
Output is correct |
27 |
Correct |
5 ms |
2392 KB |
Output is correct |
28 |
Correct |
13 ms |
604 KB |
Output is correct |
29 |
Correct |
17 ms |
3524 KB |
Output is correct |
30 |
Correct |
19 ms |
5716 KB |
Output is correct |
31 |
Correct |
11 ms |
604 KB |
Output is correct |
32 |
Correct |
19 ms |
3700 KB |
Output is correct |
33 |
Correct |
23 ms |
6748 KB |
Output is correct |
34 |
Correct |
37 ms |
10332 KB |
Output is correct |
35 |
Correct |
69 ms |
604 KB |
Output is correct |
36 |
Correct |
146 ms |
30736 KB |
Output is correct |
37 |
Correct |
67 ms |
680 KB |
Output is correct |
38 |
Correct |
102 ms |
14196 KB |
Output is correct |
39 |
Correct |
111 ms |
24980 KB |
Output is correct |
40 |
Correct |
184 ms |
39676 KB |
Output is correct |