状压DP入门——铺砖块

#include<cstdio>
#include<algorithm>
#include<cstring>
#define rep(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
long long  n,m,num,dp[150][40970],change[40970][20];
void dfs(int l,int pre,int now)
{
    if(l>m)
    return;
    if(l==m)
    {
        change[++num][0]=pre;
        change[num][1]=now;
    }
    dfs(l+1,pre<<1,now<<1|1);
    dfs(l+2,pre<<2,now<<2);
    dfs(l+1,pre<<1|1,now<<1);
}
int main()
{
    //f[i][sta]琛ㄧず鍓峣琛屽～婊″绗琲+1鐨勫奖鍝?
    while(~scanf("%d %d",&n,&m)&&n!=0&&m!=0)
    {
        if(n>m) swap(n,m);
        num=0;
        dfs(0,0,0);
        memset(dp,0,sizeof(dp));
        dp[0][0]=1;
        rep(i,1,n)
        
        {
            rep(j,1,num)
            {
                dp[i][change[j][1]]+=dp[i-1][change[j][0]]; 
            }
        }
        printf("%lld\n",dp[n][0]);
    }
 }