洛谷P1004方格取数

这道题和传纸条一样，之前的博文有讲解

代码

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int M=30;
int map[M][M];
int f[M][M][M][M];
int n;
int main()
{
    scanf("%d",&n);int x,y,z;
    while (scanf("%d%d%d",&x,&y,&z)&&x&&y&&y) map[x][y]=z;
    for (int i=1;i<=n;i++)
    for (int j=1;j<=n;j++)
    for (int k=1;k<=n;k++)
    for (int e=1;e<=n;e++)
    {
        f[i][j][k][e]=max(max(f[i-1][j][k-1][e],f[i-1][j][k][e-1]),max(f[i][j-1][k-1][e],f[i][j-1][k][e-1]))+map[i][j]+map[k][e];	
        if (i==k&&e==j) f[i][j][k][e]-=map[i][j];
    }
    cout<<f[n][n][n][n];
    return 0;
}