#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
typedef long long ll;
const int NMAX = 2e3 + 5;
const ll mod = 1e9 + 7;
ll n, s, f, dp[NMAX][NMAX], chk;
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> s >> f;
dp[0][0] = 1;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= i; j++){
if(i == s || i == f) dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
else dp[i][j] = dp[i - 1][j - 1] * (j - chk) + dp[i - 1][j + 1] * j;
dp[i][j] %= mod;
}
if(i == s || i == f) chk++;
}
cout << dp[n][1];
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
0 ms |
340 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
0 ms |
340 KB |
Output is correct |
| 3 |
Correct |
0 ms |
340 KB |
Output is correct |
| 4 |
Correct |
1 ms |
488 KB |
Output is correct |
| 5 |
Correct |
1 ms |
468 KB |
Output is correct |
| 6 |
Correct |
1 ms |
468 KB |
Output is correct |
| 7 |
Correct |
1 ms |
464 KB |
Output is correct |
| 8 |
Correct |
0 ms |
468 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
468 KB |
Output is correct |
| 11 |
Correct |
0 ms |
468 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
0 ms |
340 KB |
Output is correct |
| 3 |
Correct |
0 ms |
340 KB |
Output is correct |
| 4 |
Correct |
1 ms |
488 KB |
Output is correct |
| 5 |
Correct |
1 ms |
468 KB |
Output is correct |
| 6 |
Correct |
1 ms |
468 KB |
Output is correct |
| 7 |
Correct |
1 ms |
464 KB |
Output is correct |
| 8 |
Correct |
0 ms |
468 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
468 KB |
Output is correct |
| 11 |
Correct |
0 ms |
468 KB |
Output is correct |
| 12 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 13 |
Correct |
1 ms |
1108 KB |
Output is correct |
| 14 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 15 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 16 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 17 |
Correct |
2 ms |
1228 KB |
Output is correct |
| 18 |
Correct |
1 ms |
1108 KB |
Output is correct |
| 19 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 20 |
Correct |
1 ms |
1236 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
0 ms |
340 KB |
Output is correct |
| 3 |
Correct |
0 ms |
340 KB |
Output is correct |
| 4 |
Correct |
1 ms |
488 KB |
Output is correct |
| 5 |
Correct |
1 ms |
468 KB |
Output is correct |
| 6 |
Correct |
1 ms |
468 KB |
Output is correct |
| 7 |
Correct |
1 ms |
464 KB |
Output is correct |
| 8 |
Correct |
0 ms |
468 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
468 KB |
Output is correct |
| 11 |
Correct |
0 ms |
468 KB |
Output is correct |
| 12 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 13 |
Correct |
1 ms |
1108 KB |
Output is correct |
| 14 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 15 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 16 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 17 |
Correct |
2 ms |
1228 KB |
Output is correct |
| 18 |
Correct |
1 ms |
1108 KB |
Output is correct |
| 19 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 20 |
Correct |
1 ms |
1236 KB |
Output is correct |
| 21 |
Correct |
2 ms |
4564 KB |
Output is correct |
| 22 |
Correct |
2 ms |
4948 KB |
Output is correct |
| 23 |
Correct |
3 ms |
5588 KB |
Output is correct |
| 24 |
Correct |
14 ms |
23004 KB |
Output is correct |
| 25 |
Correct |
13 ms |
22920 KB |
Output is correct |
| 26 |
Correct |
13 ms |
22996 KB |
Output is correct |
| 27 |
Correct |
13 ms |
22868 KB |
Output is correct |
| 28 |
Correct |
10 ms |
15060 KB |
Output is correct |
