河南第六届ACM省赛（探 寻 宝 藏）（双线程DP）

题目地址：http://acm.nyist.net/JudgeOnline/problem.php?pid=712

思路：比较裸的双线程DP吧

AC代码：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <climits>
#include <cmath>
#include <cctype>
const int inf = 0x3f3f3f3f;//1061109567
typedef long long LL;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
using namespace std;
int map1[55][55];
int dp[55][55][55][55];
int main()
{
    int t,m,n;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&m,&n);
        memset(dp,0,sizeof(dp));
        for(int i=1; i<=m; i++)
        {
            for(int j=1; j<=n; j++)
            {
                scanf("%d",&map1[i][j]);
            }
        }
        for(int i=1; i<=m; i++)
        {
            for(int j=1; j<=n; j++)
            {
                for(int k=i+1; k<=m; k++)
                {
                    int l = i + j - k;
                    if(l <= 0)
                        break;
                    dp[i][j][k][l] = max(max(dp[i-1][j][k-1][l],dp[i][j-1][k][l-1]),max(dp[i-1][j][k][l-1],dp[i][j-1][k-1][l]));
                    dp[i][j][k][l] += map1[i][j] + map1[k][l];
                }
            }
        }
        printf("%d\n",dp[m-1][n][m][n-1]+map1[1][1]+map1[m][n]);
    }
    return 0;
}