HDU5729 2016 Multi-University Training Contest 1 (dp+连通图)

#include<iostream>
#include<cstdio>
using namespace std;
const int mod=1e9+7;
long long c[105][105],dp[15][15][105],pow2[105];
void init()
{
pow2[0]=c[0][0]=1;
for(int i=1;i<=100;i++)
{
pow2[i]=(pow2[i-1]*2)%mod;
c[i][0]=c[i][i]=1;
for(int j=1;j<i;j++)
c[i][j]=(c[i-1][j-1]+c[i-1][j])%mod;
}
dp[0][0][0]=dp[0][1][0]=dp[1][0][0]=1;
for(int i=1;i<=10;i++)
for(int j=1;j<=10;j++)
{
if(i==1||j==1)
{
dp[i][j][i+j-1]=1;
continue;
}
for(int k=1;k<=i*j;k++)
{
dp[i][j][k]=c[i*j][k];
for(int ii=0;ii<=i;ii++)
for(int jj=1;jj<=j;jj++)
{
if (i + j == ii + jj)
continue;
for(int kk=0;kk<=k;kk++)
{
long long temp=c[i][ii]*c[j-1][jj-1]%mod;
temp = temp*dp[ii][jj][kk] % mod;
temp = temp*c[(i-ii)*(j-jj)][k-kk];
dp[i][j][k]=((dp[i][j][k]-temp)%mod+mod)%mod;
}
}
}
}
}
int main()
{
int n,m;
init();
while(scanf("%d %d",&n,&m)!=EOF)
{
long long ans=0;
for(int i=0;i<=n*m;i++)
{
ans=(ans+dp
[m][i]*pow2[i])%mod;
}
printf("%lld\n",ans);
}
return 0;
}