uestc WHITE ALBUM

思路：

只要连接到k个房间其中一个就可以，所以可以把k个房间并起来。

然后就是克鲁斯卡尔。

 1 #include<iostream>

 2 #include<cstdio>

 3 #include<cstdlib>

 4 #include<cstring>

 5 #include<string>

 6 #include<queue>

 7 #include<algorithm>

 8 #include<map>

 9 #include<iomanip>

10 #include<climits>

11 #include<string.h>

12 #include<cmath>

13 #include<stdlib.h>

14 #include<vector>

15 #define INF 1e7

16 #define MAXN 100010

17 #define maxn 1000010

18 #define Mod 1000007

19 #define N 1010

20 using namespace std;

21 typedef long long LL;

22 

23 struct node{

24     int a, b, c;

25     bool operator < (const node a) const{

26         return c < a.c;

27     }

28 }s[N*500];

29 

30 int fa[N];

31 int n, m, k;

32 

33 int findset(int x)

34 {

35     if (fa[x] == x) return x;

36     return fa[x] = findset(fa[x]);

37 }

38 

39 void merg(int a, int b)

40 {

41     int x = findset(a);

42     int y = findset(b);

43     if (x != y) {

44         fa[x] = y;

45     }

46 }

47 

48 void init()

49 {

50     for (int i = 0; i <= n; ++i)

51         fa[i] = i;

52 }

53 

54 int main()

55 {

56     while (cin >> n >> m >> k) {

57         init();

58         int tmp, x;

59         cin >> tmp;

60         for (int i = 1; i < k; ++i) {

61             cin >> x;

62             fa[x] = tmp;

63         }

64         int a, b, c;

65         for (int i = 0; i < m; ++i) {

66             cin >> s[i].a >> s[i].b >> s[i].c;

67         }

68         sort(s,s+m);

69         int res = 0;

70         for (int i = 0; i < m; ++i) {

71             int x = findset(s[i].a);

72             int y = findset(s[i].b);

73             if (x != y) {

74                 fa[x] = y;

75                 res += s[i].c;

76             }

77         }

78         cout << res << endl;

79     }

80     return 0;

81 }