```cpp
//by 墨丽
#include<bits/stdc++.h>
using namespace std;
int n,x,y,z,a[11][11];
int dp[11][11];
int main() {
cin>>n;
while(cin>>x>>y>>z)a[x][y]=z;
for(int k=2; k<=n*2; k++)
for(int i=k-1; i>=1; i--)
for(int j=k-1; j>=1; j--) {
dp[i][j]=max(max(dp[i][j],dp[i-1][j-1]),max(dp[i-1][j],dp[i][j-1]))+a[i][k-i];
dp[i][j]+=a[j][k-j]*(i!=j);
}
printf("%d\n",dp[n][n]);
return 0;
}
```
by ☆Ork_Morry☆✔ @ 2018-10-30 21:16:01