【HDU1102】Constructing Roads（MST基础题）

最小生成树水题。prim一次AC

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

 #define typec int
 using namespace std;

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

 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 () {
     //cout << inf <<endl;
     int n;
     while (cin >> n) {
         for (int i =  ; i < n; ++ i) {
             for (int j =  ; j < n; ++ j) {
                 scanf("%d", &Map[i][j]);
             }
         }
         int ok_line; cin >> ok_line;
         for (int i = ; i < ok_line; ++ i) {
             int s, e;
             scanf("%d%d", &s, &e);
             Map[s - ][e - ] = Map[e - ][s - ] = ;
         }
         cout << prim(Map, n) << endl;
     }
     return ;
 }