1 //克鲁斯卡尔
2 #include<iostream>
3 #include<algorithm>
4 using namespace std;
5 const int maxn = 10005;
6 struct node
7 {
8 int begin, end, len;
9 }cun[maxn];
10 int n, fa[maxn], ans, m;
11
12 bool cmp(node a, node b)
13 {
14 return a.len<b.len; //按长度有小到大排序
15 }
16
17 void init()
18 {
19 for (int i = 0; i <= n; i++)
20 {
21 fa[i] = i;
22 }
23 }
24
25 int find(int x)
26 {
27 if (x == fa[x])
28 return fa[x];
29 else
30 return fa[x] = find(fa[x]);
31 }
32
33 void join(int a, int b)
34 {
35 a = find(a);
36 b = find(b);
37 if (a != b)
38 fa[b] = a;
39 }
40
41 int kruskal()
42 {
43 sort(cun, cun + m, cmp);
44 init(); //初始化并查集
45 ans = 0;
46 for (int i = 0; i<m; i++)
47 {
48 if (find(cun[i].begin) != find(cun[i].end)) //一条边的两个端点不在同一个集合，则选他，并合并
49 {
50 join(cun[i].begin, cun[i].end);
51 ans += cun[i].len;
52 }
53 }
54 return ans;
55 }
56
57 int main()
58 {
59 while (cin >> n)
60 {
61 if (n == 0) break;
62 m = n*(n - 1) / 2;
63 for (int i = 0; i<m; i++)
64 cin >> cun[i].begin >> cun[i].end >> cun[i].len;
65 cout << kruskal() << endl;
66 }
67 return 0;
68 }
1 //prim
2 #include<iostream>
3 #include<cstdio>
4 #include<cstdlib>
5 #include<cstring>
6 #include<algorithm>
7 using namespace std;
8
9 #define INF 0x7fffffff
10 # define MAXN 120
11 typedef long long int LL;
12
13 LL n, m;
14 LL cmpa[MAXN][MAXN], book[MAXN], dis[MAXN];
15
16 int main()
17 {
18 LL a, b, weight, ans, p, q, f1, f2, minn, mark;
19 while (scanf("%I64d", &n) && n)
20 {
21 //初始化 这题prime算法合适，边那摩多，都是完全图了
22 for (LL i = 0; i<MAXN; i++)
23 {
24 dis[i] = INF;
25 for (LL j = 0; j<MAXN; ++j)
26 cmpa[i][j] = INF;
27 }
28
29 memset(book, 0, sizeof(book));
30 ans = 0;
31
32 for (LL i = 0; i<n*(n - 1) / 2; ++i)
33 {
34 scanf("%I64d %I64d %I64d", &a, &b, &weight);
35 cmpa[a][b] = cmpa[b][a] = weight;
36 }
37
38 //连通图
39 book[1] = 1;
40 dis[1] = -1;
41
42 for (LL t = 1; t<n; ++t)
43 {
44 for (LL i = 2; i <= n; ++i)
45 {//更新dis中的值
46 for (LL j = 1; j <= n; ++j)
47 {
48 if (book[j] && dis[i]>cmpa[i][j])
49 { //j在树中
50 dis[i] = cmpa[i][j];
51 }
52 }
53 }
54
55 //选点建树
56 minn = INF, mark = 0;
57 for (LL i = 2; i <= n; ++i)
58 {
59 if (book[i])
60 continue;
61 else
62 {
63 if (dis[i] < minn)
64 {
65 minn = dis[i];
66 mark = i;
67 }
68 }
69 }
70
71 if (minn != INF)
72 {
73 ans += minn;
74 book[mark] = 1;
75 dis[mark] = -1;
76 }
77
78 }
79 cout << ans << endl;
80
81 }
82 return 0;
83 }
