1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
#include <algorithm>
const int mo = 9999973;
const int maxn = 105;
using namespace std;
int f[maxn][maxn][maxn], n, m;
int (int x){
return 1ll * x * (x - 1) / 2 % mo;
}
int main() 大专栏 [AHOI2009]中国象棋{
scanf("%d%d", &n, &m);
f[0][0][0] = 1;
for (int i = 1; i <= n; i++){
for (int j = 0; j <= m; j++)
for (int k = 0; j + k <= m; k++){
f[i][j][k] = f[i - 1][j][k];
if (k > 0) f[i][j][k] = (f[i][j][k] + 1ll * f[i - 1][j + 1][k - 1] * (j + 1) % mo) % mo;
if (j > 0) f[i][j][k] = (f[i][j][k] + 1ll * f[i - 1][j - 1][k] * (m - j - k + 1) % mo) % mo;
if (k > 1) f[i][j][k] = (f[i][j][k] + 1ll * f[i - 1][j + 2][k - 2] * X(j + 2) % mo) % mo;
if (k > 0) f[i][j][k] = (f[i][j][k] + 1ll * f[i - 1][j][k - 1] * j % mo * (m - j - k + 1) % mo) % mo;
if (j > 1) f[i][j][k] = (f[i][j][k] + 1ll * f[i - 1][j - 2][k] * X(m - j - k + 2) % mo) % mo;
}
}
int ans = 0;
for (int j = 0; j <= m; j++)
for (int k = 0; j + k <= m; k++)
ans = (ans + f[n][j][k]) % mo;
printf("%dn", ans);
return 0;
}
|