题目传送门
1 /*
2 此题为：HDOJ 1233 + HDOJ 1232
3 */
4 #include <cstdio>
5 #include <algorithm>
6 #include <cstring>
7 #include <cmath>
8 using namespace std;
9
10 const int MAX_N = 100 + 10;
11 int pre[MAX_N];
12 int tot;
13 int sum;
14 struct NODE
15 {
16 int x, y;
17 int len;
18 }node[MAX_N];
19
20 int find(int root)
21 {
22 int son, tmp;
23 son = root;
24
25 while (root != pre[root])
26 {
27 root = pre[root];
28 }
29 while (son != root)
30 {
31 tmp = pre[son];
32 pre[son] = root;
33 son = tmp;
34 }
35
36 return root;
37 }
38
39 bool cmp(NODE a, NODE b)
40 {
41 return a.len < b.len;
42 }
43
44 int main(void) //HDOJ 1863 畅通工程
45 {
46 //freopen ("inC.txt", "r", stdin);
47 int n, m; //n路， m村庄
48
49 while (~scanf ("%d%d", &n, &m) && n)
50 {
51 tot = m - 1;
52 for (int i=1; i<=m; ++i)
53 {
54 pre[i] = i;
55 }
56 for (int i=1; i<=n; ++i)
57 {
58 scanf ("%d%d%d", &node[i].x, &node[i].y, &node[i].len);
59 }
60 sort (node+1, node+1+n, cmp);
61 sum = 0;
62 for (int i=1; i<=n; ++i)
63 {
64 int a, b;
65 a = find (node[i].x);
66 b = find (node[i].y);
67 if (a != b)
68 {
69 pre[a] = b;
70 sum += node[i].len;
71 --tot;
72 }
73 }
74 if (tot == 0)
75 printf ("%d
", sum);
76 else
77 puts ("?");
78 }
79 }