#include <bits/stdc++.h>
using namespace std;
long long dp[2001][2001];
int main() {
int n, cs, cf; cin >> n >> cs >> cf;
for (int i = 0; i <= n;i++) for (int j = 0; j <= n; j++) dp[i][j] = 0;
dp[1][1] = 1;
for (int i = 2; i <= n; i++) {
for (int j = 1; j <= i; j++) {
if (i == cs || i == cf) {
dp[i][j] = (dp[i-1][j-1] + dp[i-1][j])%1000000007;
} else {
dp[i][j] = ((dp[i-1][j+1]*j) + dp[i-1][j-1]*(j-(i>cs)-(i>cf))) % 1000000007;
}
}
}
cout << dp[n][1] << endl;
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
512 KB |
Output is correct |
| 5 |
Correct |
5 ms |
512 KB |
Output is correct |
| 6 |
Correct |
5 ms |
512 KB |
Output is correct |
| 7 |
Correct |
5 ms |
512 KB |
Output is correct |
| 8 |
Correct |
5 ms |
512 KB |
Output is correct |
| 9 |
Correct |
5 ms |
512 KB |
Output is correct |
| 10 |
Correct |
5 ms |
512 KB |
Output is correct |
| 11 |
Correct |
5 ms |
512 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
512 KB |
Output is correct |
| 5 |
Correct |
5 ms |
512 KB |
Output is correct |
| 6 |
Correct |
5 ms |
512 KB |
Output is correct |
| 7 |
Correct |
5 ms |
512 KB |
Output is correct |
| 8 |
Correct |
5 ms |
512 KB |
Output is correct |
| 9 |
Correct |
5 ms |
512 KB |
Output is correct |
| 10 |
Correct |
5 ms |
512 KB |
Output is correct |
| 11 |
Correct |
5 ms |
512 KB |
Output is correct |
| 12 |
Correct |
6 ms |
1408 KB |
Output is correct |
| 13 |
Correct |
6 ms |
1408 KB |
Output is correct |
| 14 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 15 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 16 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 17 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 18 |
Correct |
5 ms |
1280 KB |
Output is correct |
| 19 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 20 |
Correct |
5 ms |
1408 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
512 KB |
Output is correct |
| 5 |
Correct |
5 ms |
512 KB |
Output is correct |
| 6 |
Correct |
5 ms |
512 KB |
Output is correct |
| 7 |
Correct |
5 ms |
512 KB |
Output is correct |
| 8 |
Correct |
5 ms |
512 KB |
Output is correct |
| 9 |
Correct |
5 ms |
512 KB |
Output is correct |
| 10 |
Correct |
5 ms |
512 KB |
Output is correct |
| 11 |
Correct |
5 ms |
512 KB |
Output is correct |
| 12 |
Correct |
6 ms |
1408 KB |
Output is correct |
| 13 |
Correct |
6 ms |
1408 KB |
Output is correct |
| 14 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 15 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 16 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 17 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 18 |
Correct |
5 ms |
1280 KB |
Output is correct |
| 19 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 20 |
Correct |
5 ms |
1408 KB |
Output is correct |
| 21 |
Correct |
8 ms |
6400 KB |
Output is correct |
| 22 |
Correct |
8 ms |
7040 KB |
Output is correct |
| 23 |
Correct |
10 ms |
7808 KB |
Output is correct |
| 24 |
Correct |
25 ms |
31616 KB |
Output is correct |
| 25 |
Correct |
28 ms |
31616 KB |
Output is correct |
| 26 |
Correct |
29 ms |
31616 KB |
Output is correct |
| 27 |
Correct |
25 ms |
31488 KB |
Output is correct |
| 28 |
Correct |
24 ms |
23808 KB |
Output is correct |
