#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
long long n, dp[2007][2007], f, cs, cf;
int main()
{
cin>>n>>cs>>cf;
dp[0][0]=1;
for(int i=1; i<=n; i++){
for(int j=1; j<=n; j++){
if(i==cs || i==cf){
dp[i][j]=dp[i-1][j-1]+dp[i-1][j];
continue;
}
if(i<cs) dp[i][j]=j*(dp[i-1][j-1]+dp[i-1][j+1]);
else if(i<cf) dp[i][j]=dp[i-1][j-1]*(j-1)+dp[i-1][j+1]*j;
else dp[i][j]=dp[i-1][j-1]*(j-2)+dp[i-1][j+1]*j;
}
}
cout<<dp[n][1];
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
300 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
300 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
336 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
300 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
336 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
300 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
336 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |