poj3133 插头dp

#include <iostream>
#include <cstdio>
#include <string.h>
#include <vector>
#include <algorithm>
using namespace std;
const int INF=100000000;
int nrows,ncols;
int G[10][10];
struct State
{
   int up[9];
   int left;
   int encode()const
   {
     int key=left;
     for(int i=0; i<ncols; i++)
        key=key*3+up[i];
     return key;
   }
   bool next(int row, int col, int U, int D, int L, int R, State &T)const
   {
       if( row==nrows-1 && D != 0) return false; //最下行不能有向下的插头
       if( col==ncols-1 && R !=0 ) return false; //最右列右边不能有插头
       int must_left=(col>0&&left!=0);// 是否必须要左插头
       int must_up =(row>0&&up[col]!=0);//是否必须要右插头
       if((must_left!=0 && L!=left ) || (must_left==0 && L!=0 )) return false;//左插头不匹配
       if((must_up  !=0 && U!=up[col])||(must_up==0 && U!=0 ) ) return false;//上插头不匹配
       if(must_left && must_up && left!=up[col]) return false;

       for(int i=0; i<ncols; i++)T.up[i]=up[i];
       T.up[col]=D;
       T.left=R;
      return true;
   }
};
int memo[9][9][59049];
int rec(int row, int col, const State &S)
{
    if(col==ncols){ col=0; row++;};
    if(row==nrows)return 0;
    int key=S.encode();
    int &res = memo[row][col][key];
    if(res>=0)return res;
    res=INF;
    State T;
    if(G[row][col]<=1)
    {
        if(S.next(row,col,0,0,0,0,T))res=min(res,rec(row,col+1,T));
        if(G[row][col]== 0)
            for(int t=1; t<=2 ; t++)
            {
                if(S.next(row,col,t,t,0,0,T))res=min(res,rec(row,col+1,T)+2);
                if(S.next(row,col,t,0,t,0,T))res=min(res,rec(row,col+1,T)+2);
                if(S.next(row,col,t,0,0,t,T))res=min(res,rec(row,col+1,T)+2);
                if(S.next(row,col,0,t,t,0,T))res=min(res,rec(row,col+1,T)+2);
                if(S.next(row,col,0,t,0,t,T))res=min(res,rec(row,col+1,T)+2);
                if(S.next(row,col,0,0,t,t,T))res=min(res,rec(row,col+1,T)+2);
            }

    }
    else {
        int t=G[row][col]-1;
        if(S.next(row,col,t,0,0,0,T))res=min(res,rec(row,col+1,T)+1);
        if(S.next(row,col,0,t,0,0,T))res=min(res,rec(row,col+1,T)+1);
        if(S.next(row,col,0,0,t,0,T))res=min(res,rec(row,col+1,T)+1);
        if(S.next(row,col,0,0,0,t,T))res=min(res,rec(row,col+1,T)+1);
    }
    return res;
}
int main()
{
    while(scanf("%d%d",&nrows,&ncols)==2&&nrows&&ncols)
    {
        for(int i=0; i<nrows; i++)
            for(int j=0; j<ncols; j++)
            scanf("%d",&G[i][j]);
        State S;
        memset(&S,0,sizeof(S));
        memset(memo,-1,sizeof(memo));
        int ans=rec(0,0,S);
        if(ans==INF)ans=0;
        printf("%d
",ans/2);
    }
    return 0;
}