#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using PII = pair<int, int>;
const int N = 4000;
const int M = 1e9 + 7;
int dp[N][N];
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, cs, cf;
cin >> n >> cs >> cf;
dp[1][1] = 1;
for(int i = 2; i <= n; ++i){
for(int j = 1; j <= i; ++j){
if(i == cs or i == cf) dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
else {
dp[i][j] += dp[i - 1][j + 1] * j; //merging of two component
dp[i][j] += dp[i - 1][j - 1] * j; // start of a new component
}
dp[i][j] %= M;
}
}
cout << dp[n][1]<<"\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |