#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
int dp[2005][2005];
int main() {
ifstream f("kangaroo.in");
int n, start, finish;
f >> n >> start >> finish;
f.close();
dp[0][0] = 1;
bool has_start = 0;
bool has_end = 0;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++) {
if (i == start || i == finish) {
dp[i][j] = (1LL * dp[i][j] + dp[i - 1][j] + dp[i - 1][j - 1]) % MOD;
if (i == start)
has_start = 1;
if (i == finish)
has_end = 1;
}
else {
dp[i][j] = (1LL * dp[i][j] + 1LL * (j - has_start - has_end) * dp[i - 1][j - 1] % MOD) % MOD;
dp[i][j] = (1LL * dp[i][j] + 1LL * j * dp[i - 1][j + 1] % MOD) % MOD;
}
}
ofstream g("kangaroo.out");
g << dp[n][1];
g.close();
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |