poj 2964 双进程DP

又一道双进程DP，状态转移方程如下：

f(k,i,j)=max(f(k-1,i,j),f(k-1,i-1,j),f(k-1,i,j-1),f(k-1,i-1,j-1))

然后f(k,i,j)加上(i,k-i)和(j,k-j)上的interesting locations。注意i和j相等的情况。

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int map[110][110];
int res[211][110][110];
inline int max(int a,int b,int c,int d)
{
    int s,t;
    s = a > b ? a : b;
    t = c > d ? c : d;
    return s > t ? s : t;
}
int work(int n,int m)
{
    int k,x1,x2;
    res[2][1][1]=map[1][1];
    for(k=3;k<=n+m;k++)
    {
        for(x1=1;x1<=n;x1++)
        {
            if(k-x1 < 1 || k-x1 > m) continue;
            for(x2=1;x2<=n;x2++)
            {
                if(k-x2 < 1 || k-x2 > m) continue;
                if(map[x1][k-x1]==2 || map[x2][k-x2]==2) continue;

                res[k][x1][x2]=max(res[k-1][x1][x2],res[k-1][x1-1][x2],res[k-1][x1][x2-1],res[k-1][x1-1][x2-1]);
                res[k][x1][x2]+=map[x1][k-x1];
                if(x1!=x2) res[k][x1][x2]+=map[x2][k-x2];
            }
        }
    }
    return res[n+m][n][n];
}
int main()
{
    int i,j,m,n,Case;
    char c;
    scanf("%d",&Case);
    while(Case--)
    {
        memset(res,0,sizeof(res));
        scanf("%d %d",&m,&n);
        getchar();
        for(i=1;i<=n;i++)
        {
            for(j=1;j<=m;j++)
            {
                c=getchar();
                if(c=='.') map[i][j]=0;
                if(c=='*') map[i][j]=1;
                if(c=='#') map[i][j]=2;
            }
            getchar();
        }
        printf("%d\n",work(n,m));
    }
    return 0;
}