棋盘DP尝试

讲解暂无，留坑待补。

题面

求用$1 \times 2$的骨牌平铺$n \times m$的棋盘的方案数（$1 \leq n,m \leq 12$）。

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

//data ----------
#define maxn (1<<16)
int dp[2][maxn],from[maxn],to[maxn],tcnt=0,n,m;

//method ----------
void dfs(int len,int f,int t){
    if(len>n)return;
    if(len==n){
        from[++tcnt]=f;to[tcnt]=t;return;
    }
    dfs(len+1,(f<<1)+1,t<<1);//no setting
    dfs(len+1,f<<1,(t<<1)+1);//up down
    dfs(len+2,(f<<2)+3,(t<<2)+3);//left right
}

//program ----------
int main(){
    int i,j,k,cur=0;
    //m=height, n=width
    scanf("%d%d",&n,&m);
    dfs(0,0,0);
    dp[1][(1<<n)-1]=1;
    for(i=1;i<=m;i++){
        memset(dp[cur],0x00,sizeof(dp[cur]));
        for(j=1;j<=tcnt;j++){
            dp[cur][to[j]]+=dp[cur^1][from[j]];
        }
        cur^=1;
    }
    printf("%d\n",dp[cur^1][(1<<n)-1]);
    return 0;
}