#include <iostream>
using namespace std;
typedef long long ll;
const int MX=3010, MOD=1e9+7;
int h, w, D[MX][MX];
int d(int x, int y){
int &res=D[x][y];
if(res>=0) return res;
res=d(x-1,y);
res=(res+4LL*d(x-1,y-1)*y)%MOD;
if(y>=2) res=(res+1LL*d(x-1,y-2)*(y*(y-1)/2))%MOD;
if(x>=2) res=(res+1LL*d(x-2,y-1)*y*(x-1))%MOD;
return res;
}
int main(){
ios::sync_with_stdio(0); cin.tie(0);
cin>>h>>w;
for(int i=1; i<=h; i++) for(int j=1; j<=w; j++) D[i][j]=-1;
for(int i=0; i<=h; i++) D[i][0]=1;
for(int j=1; j<=w; j++) D[0][j]=1;
cout<<(d(h,w)+MOD-1)%MOD<<'\n';
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
400 KB |
Output is correct |
| 2 |
Correct |
3 ms |
400 KB |
Output is correct |
| 3 |
Correct |
2 ms |
572 KB |
Output is correct |
| 4 |
Correct |
4 ms |
1348 KB |
Output is correct |
| 5 |
Correct |
3 ms |
1348 KB |
Output is correct |
| 6 |
Correct |
4 ms |
1592 KB |
Output is correct |
| 7 |
Correct |
3 ms |
1592 KB |
Output is correct |
| 8 |
Correct |
4 ms |
1724 KB |
Output is correct |
| 9 |
Correct |
3 ms |
1724 KB |
Output is correct |
| 10 |
Correct |
5 ms |
2028 KB |
Output is correct |
| 11 |
Correct |
3 ms |
2028 KB |
Output is correct |
| 12 |
Correct |
6 ms |
2216 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
400 KB |
Output is correct |
| 2 |
Correct |
3 ms |
400 KB |
Output is correct |
| 3 |
Correct |
2 ms |
572 KB |
Output is correct |
| 4 |
Correct |
4 ms |
1348 KB |
Output is correct |
| 5 |
Correct |
3 ms |
1348 KB |
Output is correct |
| 6 |
Correct |
4 ms |
1592 KB |
Output is correct |
| 7 |
Correct |
3 ms |
1592 KB |
Output is correct |
| 8 |
Correct |
4 ms |
1724 KB |
Output is correct |
| 9 |
Correct |
3 ms |
1724 KB |
Output is correct |
| 10 |
Correct |
5 ms |
2028 KB |
Output is correct |
| 11 |
Correct |
3 ms |
2028 KB |
Output is correct |
| 12 |
Correct |
6 ms |
2216 KB |
Output is correct |
| 13 |
Correct |
2 ms |
2216 KB |
Output is correct |
| 14 |
Correct |
8 ms |
10172 KB |
Output is correct |
| 15 |
Correct |
205 ms |
33460 KB |
Output is correct |
| 16 |
Correct |
5 ms |
33460 KB |
Output is correct |
| 17 |
Correct |
29 ms |
33460 KB |
Output is correct |
| 18 |
Correct |
58 ms |
33460 KB |
Output is correct |
| 19 |
Correct |
275 ms |
35396 KB |
Output is correct |
| 20 |
Correct |
204 ms |
35396 KB |
Output is correct |
| 21 |
Correct |
106 ms |
35396 KB |
Output is correct |
| 22 |
Correct |
112 ms |
35396 KB |
Output is correct |
| 23 |
Correct |
83 ms |
35396 KB |
Output is correct |
| 24 |
Correct |
283 ms |
36628 KB |
Output is correct |
| 25 |
Correct |
207 ms |
36628 KB |
Output is correct |
| 26 |
Correct |
264 ms |
36628 KB |
Output is correct |
| 27 |
Correct |
312 ms |
36628 KB |
Output is correct |
