【HDU1301】Jungle Roads（MST基础题）

爽爆。史上个人最快MST的记录7分40s。。一次A。

 #include <iostream>
 #include <cstring>
 #include <cstdlib>
 #include <cstdio>
 #include <cmath>
 #include <cctype>
 #include <algorithm>
 #include <numeric>

 #define typec int
 using namespace std;

 const typec inf = 0xffff;
 const int V = ;
 int vis[V]; typec lowc[V];
 int Map[V][V];

 typec prim (typec cost[][V], int n) {
     int i, j, p;
     typec minc, res = ;
     memset(vis, , sizeof (vis));
     vis[] = ;
     for (i = ; i < n; ++ i) lowc[i] = cost[][i];
     for (i = ; i < n; ++ i) {
         minc = inf; p = -;
         for (j =  ; j < n; ++ j) {
             if (  == vis[j] && minc > lowc[j]) {
                 minc = lowc[j]; p = j;
             }
         }
         if (inf == minc) return -;
         res += minc; vis[p] = ;
         for (j =  ; j < n; ++ j) {
             if ( == vis[j] && lowc[j] > cost[p][j]) {
                 lowc[j] = cost[p][j];
             }
         }
     }
     return res;
 }

 int main () {
     int n;
     while (~scanf("%d", &n)) {
         if (n == ) break;
         for (int i =  ; i < n; ++ i) {
             for (int j =  ;j < n; ++ j) {
                 if (i == j) Map[i][j] = ;
                 else Map[i][j] = inf;
             }
         }

         for (int i =  ; i < n - ; ++ i) {
             char s_c; int e_n;
             cin >> s_c >> e_n;
             for (int j =  ; j < e_n; ++ j) {
                 char e_c; int w;
                 cin >> e_c >> w;
                 Map[s_c - 'A'][e_c - 'A'] = Map[e_c - 'A'][s_c - 'A'] = min(Map[s_c - 'A'][e_c - 'A'], w);
             }
         }

         cout << prim(Map, n) << endl;
     }
     return ;
 }