P2051 [AHOI2009]中国象棋

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 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cmath>
 5 #include<queue>
 6 #include<algorithm>
 7 using namespace std;
 8 const int MAXN=201;
 9 const int mod=9999973;
10 void read(int &n)
11 {
12     char c='+';int x=0;bool flag=0;
13     while(c<'0'||c>'9')
14     {c=getchar();if(c=='-')flag=1;}
15     while(c>='0'&&c<='9')
16     {x=x*10+c-48;c=getchar();}
17     flag==1?n=-x:n=x;
18 }
19 long long  dp[MAXN][MAXN][MAXN];
20 inline int C( int num ) 
21 { // 相当于C(num,2)
22     return num*(num-1)/2;
23 }
24 int n,m;
25 int main()
26 {
27     
28     read(n);read(m);
29     dp[0][0][0]=1;
30     for(int i=0;i<n;++i)
31         for(int j=0;j<=m;++j)
32             for(int k=0;k+j<=m;++k)
33                 if(dp[i][j][k]) 
34                 { 
35                        dp[i+1][j][k]=(dp[i+1][j][k]+dp[i][j][k])%mod; 
36                        if(m-j-k>=1) dp[i+1][j+1][k]=(dp[i+1][j+1][k]+dp[i][j][k]*(m-j-k))%mod; 
37                     if(j>=1) dp[i+1][j-1][k+1]=(dp[i+1][j-1][k+1]+dp[i][j][k]*j)%mod; 
38                     if(m-j-k>=2) dp[i+1][j+2][k]=(dp[i+1][j+2][k]+dp[i][j][k]*C(m-j-k))%mod; 
39                     if(m-j-k>=1&&j>=1) dp[i+1][j][k+1]=(dp[i+1][j][k+1]+dp[i][j][k]*(m-j-k)*j)%mod; 
40                     if(j>=2) dp[i+1][j-2][k+2]=(dp[i+1][j-2][k+2]+dp[i][j][k]*C(j))%mod; 
41                    }
42     long long ans=0;
43     for(int i=0;i<=m;++i)
44         for(int j=0;i+j<=m;++j)
45             ans=(ans+dp[n][i][j])%mod;
46     printf("%lld",ans);
47     return 0;
48 }