#include <bits/stdc++.h>
using namespace std;
int n, a, b, md = 1e9 + 7; long long dp[2005][2005];
int main(){
cin >> n >> a >> b; dp[0][0] = 1;
for (int i = 1; i <= n; i++){
for (int j = 1; j <= n; j++){
if (i == a or i == b)
dp[i][j] = (dp[i - 1][j] + dp[i - 1][j - 1]) % md;
else
dp[i][j] = (dp[i - 1][j + 1] * j + dp[i - 1][j - 1] * (j - (i > a) - (i > b))) % md;
}
}
cout<<dp[n][1]<<endl;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
0 ms |
332 KB |
Output is correct |
| 4 |
Correct |
0 ms |
460 KB |
Output is correct |
| 5 |
Correct |
1 ms |
460 KB |
Output is correct |
| 6 |
Correct |
0 ms |
460 KB |
Output is correct |
| 7 |
Correct |
1 ms |
460 KB |
Output is correct |
| 8 |
Correct |
0 ms |
460 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
460 KB |
Output is correct |
| 11 |
Correct |
1 ms |
460 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
0 ms |
332 KB |
Output is correct |
| 4 |
Correct |
0 ms |
460 KB |
Output is correct |
| 5 |
Correct |
1 ms |
460 KB |
Output is correct |
| 6 |
Correct |
0 ms |
460 KB |
Output is correct |
| 7 |
Correct |
1 ms |
460 KB |
Output is correct |
| 8 |
Correct |
0 ms |
460 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
460 KB |
Output is correct |
| 11 |
Correct |
1 ms |
460 KB |
Output is correct |
| 12 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 13 |
Correct |
1 ms |
1228 KB |
Output is correct |
| 14 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 15 |
Correct |
2 ms |
1356 KB |
Output is correct |
| 16 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 17 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 18 |
Correct |
1 ms |
1228 KB |
Output is correct |
| 19 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 20 |
Correct |
1 ms |
1356 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
0 ms |
332 KB |
Output is correct |
| 4 |
Correct |
0 ms |
460 KB |
Output is correct |
| 5 |
Correct |
1 ms |
460 KB |
Output is correct |
| 6 |
Correct |
0 ms |
460 KB |
Output is correct |
| 7 |
Correct |
1 ms |
460 KB |
Output is correct |
| 8 |
Correct |
0 ms |
460 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
460 KB |
Output is correct |
| 11 |
Correct |
1 ms |
460 KB |
Output is correct |
| 12 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 13 |
Correct |
1 ms |
1228 KB |
Output is correct |
| 14 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 15 |
Correct |
2 ms |
1356 KB |
Output is correct |
| 16 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 17 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 18 |
Correct |
1 ms |
1228 KB |
Output is correct |
| 19 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 20 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 21 |
Correct |
5 ms |
6220 KB |
Output is correct |
| 22 |
Correct |
7 ms |
6860 KB |
Output is correct |
| 23 |
Correct |
7 ms |
7736 KB |
Output is correct |
| 24 |
Correct |
38 ms |
31556 KB |
Output is correct |
| 25 |
Correct |
36 ms |
31640 KB |
Output is correct |
| 26 |
Correct |
36 ms |
31652 KB |
Output is correct |
| 27 |
Correct |
37 ms |
31436 KB |
Output is correct |
| 28 |
Correct |
23 ms |
23712 KB |
Output is correct |
