#include<bits/stdc++.h>
using namespace std;
long long a,b,c,d,e,i,j,ii,jj,zx,xc,dp[3004][3004],mod=1000000007LL;
int main(){
ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>a>>b;
dp[1][0]=1;
for(i=1; i<a; i++){
for(j=0; j<=min(b,i-1); j++){
dp[i+1][j]+=dp[i][j]*(j+1);
dp[i+1][j+1]+=dp[i][j]*(i-j);
}
}
cout<<dp[a][b-1];
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
1 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
364 KB |
Output is correct |
4 |
Correct |
1 ms |
364 KB |
Output is correct |
5 |
Correct |
1 ms |
364 KB |
Output is correct |
6 |
Correct |
1 ms |
364 KB |
Output is correct |
7 |
Correct |
1 ms |
364 KB |
Output is correct |
8 |
Correct |
1 ms |
364 KB |
Output is correct |
9 |
Correct |
1 ms |
364 KB |
Output is correct |
10 |
Correct |
1 ms |
364 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
1 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
364 KB |
Output is correct |
4 |
Correct |
1 ms |
364 KB |
Output is correct |
5 |
Correct |
1 ms |
364 KB |
Output is correct |
6 |
Correct |
1 ms |
364 KB |
Output is correct |
7 |
Correct |
1 ms |
364 KB |
Output is correct |
8 |
Correct |
1 ms |
364 KB |
Output is correct |
9 |
Correct |
1 ms |
364 KB |
Output is correct |
10 |
Correct |
1 ms |
364 KB |
Output is correct |
11 |
Incorrect |
1 ms |
748 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
1 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
364 KB |
Output is correct |
4 |
Correct |
1 ms |
364 KB |
Output is correct |
5 |
Correct |
1 ms |
364 KB |
Output is correct |
6 |
Correct |
1 ms |
364 KB |
Output is correct |
7 |
Correct |
1 ms |
364 KB |
Output is correct |
8 |
Correct |
1 ms |
364 KB |
Output is correct |
9 |
Correct |
1 ms |
364 KB |
Output is correct |
10 |
Correct |
1 ms |
364 KB |
Output is correct |
11 |
Incorrect |
1 ms |
748 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
1 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
364 KB |
Output is correct |
4 |
Correct |
1 ms |
364 KB |
Output is correct |
5 |
Correct |
1 ms |
364 KB |
Output is correct |
6 |
Correct |
1 ms |
364 KB |
Output is correct |
7 |
Correct |
1 ms |
364 KB |
Output is correct |
8 |
Correct |
1 ms |
364 KB |
Output is correct |
9 |
Correct |
1 ms |
364 KB |
Output is correct |
10 |
Correct |
1 ms |
364 KB |
Output is correct |
11 |
Incorrect |
1 ms |
748 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |