bzoj1925 [Sdoi2010]地精部落

 1 #include<cstdio>
 2 #include<vector>
 3 using namespace std;
 4 const int N  = 4210;
 5 int n,P,i,j;
 6 vector<int> c[N];
 7 long long f[N],g[N];
 8 int main()
 9 {
10     scanf("%d%d",&n,&P);
11     for (i=0;i<=n;i++)
12     {
13         c[i].push_back(1);
14         for (j=1;j<=i;j++)
15         {
16             int tmp=0;
17             tmp=c[i-1][j-1];
18             if (j<=i-1) tmp=(tmp+c[i-1][j])%P;
19             c[i].push_back(tmp);
20         }
21     }
22     g[1]=g[0]=1;
23     for (i=2;i<=n;i++)
24     for (j=0;j<i;j++)
25     {
26         (f[i]+=(g[j]*g[i-1-j])%P*c[i-1][j])%=P;
27         if (j&1)
28         (g[i]+=(g[j]*g[i-1-j])%P*c[i-1][j])%=P;
29     }
30     printf("%lld",f[n]);
31 }