pipioj 1454: 網絡工程師（kruskal）

 1 #define bug(x) cout<<#x<<" is "<<x<<endl
 2 #define IO std::ios::sync_with_stdio(0)
 3 #include <bits/stdc++.h>
 4 using namespace  std;
 5 typedef long long ll;
 6 #define mk make_pair
 7 #define pb push_back
 8 const int inf=2147483647;
 9 const int N=1e3+10;
10 int fa[N],a[N];
11 vector<int>g[N],v[N];
12 int find(int x){
13     return fa[x]==x?x:fa[x]=find(fa[x]);
14 }
15 int n,m,k;
16 struct node{
17     int x,y,w;
18 }b[100005];
19 
20 
21 bool cmp(node p,node q){
22     return p.w<q.w;
23 }
24 int main(){
25     IO;
26     while(cin>>n>>m>>k){
27         for(int i=1;i<=n;i++)fa[i]=i;
28         for(int i=1;i<=n;i++){
29             cin>>a[i];
30         }
31         for(int i=1;i<=m;i++){
32             int x,y;
33             cin>>x>>y;
34             b[i].x=x;
35             b[i].y=y;
36             if(a[x]==a[y]){
37                 b[i].w=0;
38             }
39             else{
40                 b[i].w=1;
41             }
42         }
43         sort(b+1,b+1+m,cmp);
44         int ans=0,cnt=0;
45         for(int i=1;i<=m;i++){
46             //bug(i);
47             int x=b[i].x;
48             int y=b[i].y;
49             x=find(x);
50             y=find(y);
51             if(x!=y){
52                 ans+=b[i].w;
53                 fa[x]=y;
54                 cnt++;
55             }
56             if(cnt==n-1)break;
57         }
58         cout<<ans<<endl;
59     }
60 
61 }
62 /*
63 4 4 4
64 1 2 3 4
65 1 2
66 2 3
67 3 4
68 4 1
69 
70 4 3 2
71 1 1 2 2
72 1 3
73 2 3
74 3 4
75 */