#include <bits/stdc++.h>
using namespace std;typedef long long p;p m=1e9+7;p d[2001][2001];int main(){int n,a,b;cin>>n>>a>>b;d[0][0]=1;for(p i=1;i<=n;i++){for(p j=1;j<=i;j++){if(i==a||i==b)d[i][j]=(d[i-1][j-1]+d[i-1][j])%m;else d[i][j]=(d[i-1][j+1]*j%m+d[i-1][j-1]*(j-(i>a)-(i>b))%m)%m;}}cout<<d[n][1];return 0;}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
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 |
0 ms |
468 KB |
Output is correct |
5 |
Correct |
0 ms |
468 KB |
Output is correct |
6 |
Correct |
0 ms |
468 KB |
Output is correct |
7 |
Correct |
0 ms |
468 KB |
Output is correct |
8 |
Correct |
0 ms |
468 KB |
Output is correct |
9 |
Correct |
1 ms |
468 KB |
Output is correct |
10 |
Correct |
0 ms |
468 KB |
Output is correct |
11 |
Correct |
1 ms |
468 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
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 |
0 ms |
468 KB |
Output is correct |
5 |
Correct |
0 ms |
468 KB |
Output is correct |
6 |
Correct |
0 ms |
468 KB |
Output is correct |
7 |
Correct |
0 ms |
468 KB |
Output is correct |
8 |
Correct |
0 ms |
468 KB |
Output is correct |
9 |
Correct |
1 ms |
468 KB |
Output is correct |
10 |
Correct |
0 ms |
468 KB |
Output is correct |
11 |
Correct |
1 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 |
1 ms |
1236 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 |
# |
Verdict |
Execution time |
Memory |
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 |
0 ms |
468 KB |
Output is correct |
5 |
Correct |
0 ms |
468 KB |
Output is correct |
6 |
Correct |
0 ms |
468 KB |
Output is correct |
7 |
Correct |
0 ms |
468 KB |
Output is correct |
8 |
Correct |
0 ms |
468 KB |
Output is correct |
9 |
Correct |
1 ms |
468 KB |
Output is correct |
10 |
Correct |
0 ms |
468 KB |
Output is correct |
11 |
Correct |
1 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 |
1 ms |
1236 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 |
6 ms |
4564 KB |
Output is correct |
22 |
Correct |
7 ms |
4964 KB |
Output is correct |
23 |
Correct |
7 ms |
5572 KB |
Output is correct |
24 |
Correct |
44 ms |
22916 KB |
Output is correct |
25 |
Correct |
41 ms |
22884 KB |
Output is correct |
26 |
Correct |
42 ms |
22960 KB |
Output is correct |
27 |
Correct |
41 ms |
22752 KB |
Output is correct |
28 |
Correct |
23 ms |
15088 KB |
Output is correct |