【HDU1233】还是畅通工程（MST基础题）

无坑，裸题。直接敲就恩那个AC。

 

 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 int

10 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 }