1 #include <iostream> 2 #include <cstring> 3 #include <cstdio> 4 #include <cmath> 5 #include <cctype> 6 #include <algorithm> 7 #include <numeric> 8  9 #define typec int10 using namespace std;11 12 const int V = 105;13 const int inf = 0xffff;14 int vis[V]; typec lowc[V], Map[V][V];15 16 typec prim (typec cost[][V], int n) {17     int i, j, p;18     typec minc, res = 0;19     memset(vis, 0, sizeof(vis));20     vis[0] = 1;21     for (int i = 1; i < n; ++ i) lowc[i] = cost[0][i];22     for (int i = 1; i < n; ++ i) {23         minc = inf; p = -1;24         for (j = 0; j < n; ++ j) {25             if (0 == vis[j] && minc > lowc[j]) {26                 minc = lowc[j]; p = j;27             }28         }29         if (inf == minc) return -1;30         res += minc; vis[p] = 1;31         for (j = 0; j < n; ++ j) {32             if (0 == vis[j] && lowc[j] > cost[p][j])33             lowc[j] = cost[p][j];34         }35     }36     return res;37 }38 39 int main () {40     int n;41     while (~scanf("%d", &n) && n) {42         for (int i = 0; i < V; ++ i) {43             for (int j = 0; j < V; ++ j) {44                 if (i == j) Map[i][j] = 0;45                     else Map[i][j] = inf;46             }47         }48         for (int i = 0; i < n * (n - 1) / 2; ++i) {49             int x, y, c; scanf("%d%d%d", &x, &y, &c);50             if (x == y) continue;51             Map[x - 1][y - 1] = Map[y - 1][x - 1] = min(Map[x - 1][y - 1], c);52         }53         cout << prim(Map, n) << endl;54     }55     return 0;56 }