#include <bits/stdc++.h>
using namespace std;
const int N=305;
long long dp[N][N][N];
int n,m;
long long mod=1e9+7;
long long bt(int i, int j0, int j1)
{
if(i==n)
{
if(j0==m||j1!=0)
return 0;
return 1;
}
if(dp[i][j0][j1]!=-1)
return dp[i][j0][j1];
long long x=bt(i+1,j0,j1);
x%=mod;
if(j0)
x+=bt(i+1,j0-1,j1+1)*j0+bt(i+1,j0-1,j1)*j0*4;
x%=mod;
if(j1)
x+=bt(i+1,j0,j1-1)*j1;
x%=mod;
if(j0>1)
x+=(bt(i+1,j0-2,j1)*j0*(j0-1))/2;
x%=mod;
dp[i][j0][j1]=x;
return x;
}
int main()
{
cin>>n>>m;
memset(dp,-1,sizeof dp);
cout<<bt(0,m,0)<<endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
222328 KB |
Output is correct |
2 |
Correct |
191 ms |
222440 KB |
Output is correct |
3 |
Correct |
176 ms |
222528 KB |
Output is correct |
4 |
Correct |
201 ms |
222744 KB |
Output is correct |
5 |
Correct |
205 ms |
222744 KB |
Output is correct |
6 |
Correct |
260 ms |
222744 KB |
Output is correct |
7 |
Correct |
196 ms |
222744 KB |
Output is correct |
8 |
Correct |
236 ms |
222748 KB |
Output is correct |
9 |
Correct |
178 ms |
222748 KB |
Output is correct |
10 |
Correct |
480 ms |
222764 KB |
Output is correct |
11 |
Correct |
178 ms |
222764 KB |
Output is correct |
12 |
Correct |
1511 ms |
222764 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
222328 KB |
Output is correct |
2 |
Correct |
191 ms |
222440 KB |
Output is correct |
3 |
Correct |
176 ms |
222528 KB |
Output is correct |
4 |
Correct |
201 ms |
222744 KB |
Output is correct |
5 |
Correct |
205 ms |
222744 KB |
Output is correct |
6 |
Correct |
260 ms |
222744 KB |
Output is correct |
7 |
Correct |
196 ms |
222744 KB |
Output is correct |
8 |
Correct |
236 ms |
222748 KB |
Output is correct |
9 |
Correct |
178 ms |
222748 KB |
Output is correct |
10 |
Correct |
480 ms |
222764 KB |
Output is correct |
11 |
Correct |
178 ms |
222764 KB |
Output is correct |
12 |
Correct |
1511 ms |
222764 KB |
Output is correct |
13 |
Correct |
199 ms |
222764 KB |
Output is correct |
14 |
Incorrect |
189 ms |
222764 KB |
Output isn't correct |
15 |
Halted |
0 ms |
0 KB |
- |