bzoj3195 [Jxoi2012]奇怪的道路——状压DP

题目：https://www.lydsy.com/JudgeOnline/problem.php?id=3195

看到数据范围就应该想到状压呢...

题解(原来是这样)：https://www.cnblogs.com/LadyLex/p/7252789.html

代码如下：

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
typedef long long ll;
int n,m,k;
ll f[35][35][1<<9][10],z[10],mod=1000000007;
int main()
{scanf("%d%d%d",&n,&m,&k);z[0]=1; for(int i=1;i<=k+1;i++)z[i]=(z[i-1]<<1);f[2][0][0][0]=1;for(int i=2;i<=n;i++)for(int j=0;j<=m;j++)for(int s=0;s<z[k+1];s++){for(int l=0;l<k;l++){(f[i][j][s][l+1]+=f[i][j][s][l])%=mod;if(j<m&&i-(k-l)>0)(f[i][j+1][s^z[k]^z[l]][l]+=f[i][j][s][l])%=mod;}if((s&1)==0)f[i+1][j][s>>1][0]=f[i][j][s][k];}printf("%lld",f[n+1][m][0][0]);return 0;
}