func_code_string: #include <bits/stdc++.h>   using namespace std;   struct ac {     int x, y, z;   } p[3000];   int mo[3000];   vector<pair<int, int> > pr;   int main() {     int n;     scanf( %d , &n);     for (int i = 1; i <= n; ++i) {       scanf( %d%d%d , &p[i].x, &p[i].y, &p[i].z);     }     for (int i = 1; i <= n; ++i) {       int d = 1e9, f = 0;       if (mo[i] == 1) continue;       for (int j = 1; j <= n; ++j) {         if (mo[j] == 1 || i == j) continue;         int td =             abs(p[i].x - p[j].x) + abs(p[j].y - p[i].y) + abs(p[j].z - p[i].z);         if (td < d) {           f = j;           d = td;         }       }       mo[i] = mo[f] = 1;       cout << i <<     << f << endl;     }     return 0;   }   