```cpp
//代码如下:
#include<bits/stdc++.h>
using namespace std;
int dp[13][13][13][13],a[13][13],n,x,y,z,i,j,k,l;
int main(){
cin>>n;
while(cin>>x>>y>>z&&x&&y&&z)a[x][y]=z;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
for(k=1;k<=n;k++)
for(l=1;l<=n;l++){
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][l-1],dp[i][j-1][k-1][l]))+a[i][j]+a[k][l];
if(i==k&&j==l)dp[i][j][k][l]-=a[i][j];
}
cout<<dp[n][n][n][n];
}
by zyc220207 @ 2023-02-21 10:20:30