双线程dp

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<cctype>
#include<algorithm>
#include <vector>
#include <queue>

using namespace std;
#define INF 0x3f3f3f3f
#define N 55

int maps[N][N];
int dp[N][N][N][N];

int main()
{
    int T, m, n;
    scanf("%d", &T);

    while(T--)
    {
        scanf("%d%d", &m, &n);
        for(int i=1; i<=m; i++)
        for(int j=1; j<=n; j++)
            scanf("%d", &maps[i][j]);

        memset(dp, 0, sizeof(dp));

        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 || l>n) break;
            dp[i][j][k][l]=max(max(dp[i-1][j][k][l-1], dp[i-1][j][k-1][l]),
                               max(dp[i][j-1][k-1][l], dp[i][j-1][k][l-1]))+maps[i][j]+maps[k][l];
        }
        printf("%d\n", max(max(dp[m-1][n][m][n-1], dp[m-1][n][m-1][n]),
                               max(dp[m][n-1][m-1][n], dp[m][n-1][m-1][n]))+maps[m][n]);
    }
    return 0;
}