#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long N = 3010;
long long dp[N][N];
long long Recur(long long row, long long col) {
if(row < 0 || col < 0)
return 0;
if(row == 0 || col == 0)
return 1;
if(dp[row][col] != -1)
return dp[row][col];
long long ans = 0, temp = 0;
//the row is empty
temp = Recur(row, col - 1);
ans = temp;
//1 tent facing anywhere
temp = ((Recur(row - 1, col - 1) * row) % MOD * 4) % MOD;
ans = (ans + temp) % MOD;
//2 tents facing each other (row-wise)
temp = (Recur(row - 2, col - 1) * (((row * (row - 1)) / 2) % MOD)) % MOD;
ans = (ans + temp) % MOD;
//2 tents facing each other (column-wise)
temp = (Recur(row - 1, col - 2));
long long x = row * (col - 1) % MOD;
temp *= x;
temp %= MOD;
ans = (ans + temp) % MOD;
dp[row][col] = ans;
return ans;
}
void Solve() {
long long n, m;
cin >> n >> m;
for(long long i = 0; i <= n; i++) {
for(long long j = 0; j <= m; j++) {
dp[i][j] = -1;
}
}
long long ans = Recur(n, m) - 1;
if(ans < 0)
ans += MOD;
cout << ans << endl;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
Solve();
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
384 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
1152 KB |
Output is correct |
5 |
Correct |
5 ms |
768 KB |
Output is correct |
6 |
Correct |
5 ms |
1408 KB |
Output is correct |
7 |
Correct |
5 ms |
896 KB |
Output is correct |
8 |
Correct |
5 ms |
1408 KB |
Output is correct |
9 |
Correct |
6 ms |
896 KB |
Output is correct |
10 |
Correct |
6 ms |
1664 KB |
Output is correct |
11 |
Correct |
5 ms |
512 KB |
Output is correct |
12 |
Correct |
9 ms |
2304 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
384 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
1152 KB |
Output is correct |
5 |
Correct |
5 ms |
768 KB |
Output is correct |
6 |
Correct |
5 ms |
1408 KB |
Output is correct |
7 |
Correct |
5 ms |
896 KB |
Output is correct |
8 |
Correct |
5 ms |
1408 KB |
Output is correct |
9 |
Correct |
6 ms |
896 KB |
Output is correct |
10 |
Correct |
6 ms |
1664 KB |
Output is correct |
11 |
Correct |
5 ms |
512 KB |
Output is correct |
12 |
Correct |
9 ms |
2304 KB |
Output is correct |
13 |
Correct |
5 ms |
512 KB |
Output is correct |
14 |
Correct |
9 ms |
9728 KB |
Output is correct |
15 |
Correct |
234 ms |
55428 KB |
Output is correct |
16 |
Correct |
18 ms |
4224 KB |
Output is correct |
17 |
Correct |
53 ms |
13056 KB |
Output is correct |
18 |
Correct |
58 ms |
17152 KB |
Output is correct |
19 |
Correct |
291 ms |
63232 KB |
Output is correct |
20 |
Correct |
231 ms |
51148 KB |
Output is correct |
21 |
Correct |
148 ms |
34048 KB |
Output is correct |
22 |
Correct |
132 ms |
35584 KB |
Output is correct |
23 |
Correct |
32 ms |
27136 KB |
Output is correct |
24 |
Correct |
410 ms |
71416 KB |
Output is correct |
25 |
Correct |
323 ms |
61568 KB |
Output is correct |
26 |
Correct |
335 ms |
67192 KB |
Output is correct |
27 |
Correct |
475 ms |
69368 KB |
Output is correct |