#include <bits/stdc++.h>
#define int long long
using namespace std;
int memo[3005][3005];
const int mod = 1000000007;
int dp(int H, int W){ ///ways such that the topmost row and rightmost column are occupied
if(W < 0 || W < 0) return 0;
if(W == 0 || H == 0) return 1;
if(memo[H][W] != -1) return memo[H][W];
int ans = 0;
if(H == 1){
ans = 4*W + 1;
ans += (W-1)*W/2;
return ans;
}
///new row is empty
ans += dp(H-1,W);
///new row is 1 thing facing nothing
ans += 4*dp(H-1,W-1)*W;
///new row is 2 things facing each other
ans += dp(H-1,W-2) * (W) * (W-1) / 2;
///new row is south, and north is somwhere below
ans += dp(H-2, W-1) * W * (H-1);
ans %= mod;
memo[H][W] = ans;
return ans;
}
signed main(){
int H, W; cin >> H >> W;
memset(memo, -1, sizeof(memo));
int ans = dp(H,W);
ans--;
if(ans < 0) ans += mod;
cout << ans;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
42 ms |
71032 KB |
Output is correct |
| 2 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 3 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 4 |
Correct |
38 ms |
71032 KB |
Output is correct |
| 5 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 6 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 7 |
Correct |
43 ms |
71160 KB |
Output is correct |
| 8 |
Correct |
40 ms |
71032 KB |
Output is correct |
| 9 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 10 |
Correct |
43 ms |
71036 KB |
Output is correct |
| 11 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 12 |
Correct |
41 ms |
71032 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
42 ms |
71032 KB |
Output is correct |
| 2 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 3 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 4 |
Correct |
38 ms |
71032 KB |
Output is correct |
| 5 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 6 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 7 |
Correct |
43 ms |
71160 KB |
Output is correct |
| 8 |
Correct |
40 ms |
71032 KB |
Output is correct |
| 9 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 10 |
Correct |
43 ms |
71036 KB |
Output is correct |
| 11 |
Correct |
39 ms |
71032 KB |
Output is correct |
| 12 |
Correct |
41 ms |
71032 KB |
Output is correct |
| 13 |
Correct |
44 ms |
71004 KB |
Output is correct |
| 14 |
Correct |
40 ms |
71168 KB |
Output is correct |
| 15 |
Correct |
182 ms |
71168 KB |
Output is correct |
| 16 |
Correct |
42 ms |
71040 KB |
Output is correct |
| 17 |
Correct |
53 ms |
71032 KB |
Output is correct |
| 18 |
Correct |
68 ms |
71160 KB |
Output is correct |
| 19 |
Correct |
196 ms |
71160 KB |
Output is correct |
| 20 |
Correct |
162 ms |
71160 KB |
Output is correct |
| 21 |
Correct |
108 ms |
71160 KB |
Output is correct |
| 22 |
Correct |
118 ms |
71168 KB |
Output is correct |
| 23 |
Correct |
78 ms |
71288 KB |
Output is correct |
| 24 |
Correct |
237 ms |
71160 KB |
Output is correct |
| 25 |
Correct |
189 ms |
71168 KB |
Output is correct |
| 26 |
Correct |
211 ms |
71228 KB |
Output is correct |
| 27 |
Correct |
223 ms |
71160 KB |
Output is correct |
