#include<bits/stdc++.h>
#define MOD ((long long)1e9+7)
using namespace std;
int n,m;
long long dp[3005][3005];
int main() {
cin >> n >> m;
dp[0][0] = 1LL;
for(int i=0; i<n; i++) {
for(int j=0; j<=m; j++) {
if(j+2<=m) {
dp[i+1][j+2] += (((m-j)*(m-j-1LL)/2)%MOD) * dp[i][j];
dp[i+1][j+2] %= MOD;
}
if(j<m) {
dp[i+1][j+1] += dp[i][j] * (m-j) * 4LL;
dp[i+1][j+1] %= MOD;
}
if(i<n-1) {
dp[i+2][j+1] += dp[i][j] * (((long long)m-j)*(i+1))%MOD;
}
}
for(int j=0; j<=m; j++) {
dp[i+1][j] += dp[i][j];
}
}
long long ans = 0;
for(int j=1; j<=m; j++) {
ans += dp[n][j];
}
cout << ans%MOD << endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
0 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
492 KB |
Output is correct |
4 |
Correct |
1 ms |
1132 KB |
Output is correct |
5 |
Correct |
1 ms |
748 KB |
Output is correct |
6 |
Correct |
1 ms |
1388 KB |
Output is correct |
7 |
Correct |
1 ms |
876 KB |
Output is correct |
8 |
Correct |
1 ms |
1516 KB |
Output is correct |
9 |
Correct |
1 ms |
896 KB |
Output is correct |
10 |
Correct |
2 ms |
1772 KB |
Output is correct |
11 |
Correct |
1 ms |
364 KB |
Output is correct |
12 |
Correct |
3 ms |
2284 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
364 KB |
Output is correct |
2 |
Correct |
0 ms |
364 KB |
Output is correct |
3 |
Correct |
1 ms |
492 KB |
Output is correct |
4 |
Correct |
1 ms |
1132 KB |
Output is correct |
5 |
Correct |
1 ms |
748 KB |
Output is correct |
6 |
Correct |
1 ms |
1388 KB |
Output is correct |
7 |
Correct |
1 ms |
876 KB |
Output is correct |
8 |
Correct |
1 ms |
1516 KB |
Output is correct |
9 |
Correct |
1 ms |
896 KB |
Output is correct |
10 |
Correct |
2 ms |
1772 KB |
Output is correct |
11 |
Correct |
1 ms |
364 KB |
Output is correct |
12 |
Correct |
3 ms |
2284 KB |
Output is correct |
13 |
Correct |
1 ms |
364 KB |
Output is correct |
14 |
Correct |
6 ms |
9708 KB |
Output is correct |
15 |
Correct |
105 ms |
55240 KB |
Output is correct |
16 |
Correct |
7 ms |
4076 KB |
Output is correct |
17 |
Correct |
25 ms |
12928 KB |
Output is correct |
18 |
Correct |
28 ms |
17132 KB |
Output is correct |
19 |
Incorrect |
112 ms |
63084 KB |
Output isn't correct |
20 |
Halted |
0 ms |
0 KB |
- |