BZOJ 3195 DP

http://www.cnblogs.com/CXCXCXC/p/5093584.html

//By SiriusRen#include <cstdio>using namespace std;int n,m,K,mod=1000000007,f[33][33][666][9];int main(){    scanf("%d%d%d",&n,&m,&K);    f[1][0][0][0]=1;    for(int i=1;i<=n;i++)        for(int j=0;j<=m;j++)            for(int k=0;k<1<<(K+1);k++){                for(int l=0;l<K;l++){                    (f[i][j][k][l+1]+=f[i][j][k][l])%=mod;                    if(i-K+l>0)(f[i][j+1][k^(1<<l)^(1<<K)][l]+=f[i][j][k][l])%=mod;                }                if(!(k&1))(f[i+1][j][k>>1][0]+=f[i][j][k][K])%=mod;            }    printf("%d\n",f[n+1][m][0][0]);}