【luogu P1536 村村通】 题解

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 using namespace std;
 5 const int maxn = 1001;
 6 int fa[maxn], n, m, tot = 0, ans[100001];
 7 struct edge{
 8     int u,v;
 9 }e[1000001];
10 int find(int x)
11 {
12     return fa[x]==x?x:fa[x]=find(fa[x]);
13 }
14 int main()
15 {
16     int k = 0;
17     while(scanf("%d",&n))
18     {
19         if(n == 0) 
20         {
21             for(int i = 1; i <= k; i++)
22             printf("%d\n",ans[i]);    
23             return 0;
24         }
25         scanf("%d",&m);
26         tot = 0;
27         k++;
28         for(int i = 1; i <= n; i++)
29         fa[i] = i;
30         for(int i = 1; i <= m; i++)
31         {
32             scanf("%d%d",&e[i].u, &e[i].v);
33             {
34                 int x = find(e[i].u);
35                 int y = find(e[i].v);
36                 if(x!=y) 
37                 {
38                     fa[y] = x;    tot++;
39                 }
40             }
41         }
42         ans[k] = n - tot -1;
43     }
44     
45 }