HDU 3367 Pseudoforest

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<cstring>
 5 
 6 using namespace std;
 7 
 8 typedef struct nod
 9 {
10     int x,y,c;
11 } node;
12 node a[100010];
13 
14 bool op(node a,node b)
15 {
16     return a.c>b.c;
17 }
18 
19 int father[10010];
20 bool flag[10010];
21 
22 void clean_father(int n)
23 {
24     for (int i=0;i<n;i++) father[i]=i;
25 } 
26 
27 int getfather(int x)
28 {
29     if (father[x]!=x) father[x]=getfather(father[x]);
30     return father[x];
31 }
32 
33 void link(int x,int y)
34 {
35     father[getfather(x)]=getfather(y);
36 } 
37 
38 int main()
39 {
40     int n,m;
41     while (scanf("%d%d",&n,&m))
42     {
43         if (n==0&&m==0) break;
44         
45         for (int i=1;i<=m;i++) scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].c);
46         sort(&a[1],&a[m+1],op);
47         
48         clean_father(n);
49         memset(flag,0,sizeof(flag));
50         int ans=0;
51         for (int i=1;i<=m;i++)
52         if (getfather(a[i].x)!=getfather(a[i].y))
53         {
54             if (!(flag[getfather(a[i].x)]&&flag[getfather(a[i].y)]))
55             {
56                 
57                 if (flag[getfather(a[i].x)]||flag[getfather(a[i].y)])
58                 {
59                     flag[getfather(a[i].x)]=true;
60                     flag[getfather(a[i].y)]=true;
61                 }
62                 link(a[i].x,a[i].y);
63                 ans+=a[i].c;
64             }
65         } else 
66         if (!flag[getfather(a[i].x)])
67         {
68             ans+=a[i].c;
69             flag[getfather(a[i].x)]=true;
70         }
71         
72         printf("%d\n",ans);
73     }
74     
75     return 0;
76 }