Date：2019-06-23 13:42:53
1 //定义
2 int father[N]; //father[1]=2,即2是1的父亲，根结点用father[i]=i表示
3
4 //初始化
5 for(int i=1; i<=N; i++)
6 father[i]=i; //初始时有N个独立的集合
7
8 //查找
9 //对于给定的结点，寻找其根结点
10 int Find(int x)
11 {
12 if(father[x] == x)
13 return x;
14 Find(father[x]);
15 }
16
17 //合并
18 void Union(int a, int b)
19 {
20 int fa = Find(a);
21 int fb = Find(b);
22 father[fb] = fa; //不能用father[a]=b
23 Find2(b); //将fb中的结点更新至fa
24 }
25
26
27 //路径压缩
28 //把当前查询结点的路径上所有的结点的父亲都指向根结点
29 int Find2(int x)
30 {
31 int r = x;
32 while(x != father[x])
33 x = father[x];
34 //此处x已经是根结点
35 while(r != father[r])
36 {
37 int z = r;
38 r = father[r];
39 father[z] = x;
40 }
41 }
42
43 //递归写法
44 int Find2(int x)
45 {
46 if(x == father[x])
47 return x;
48 fathre[x] = Find2(father[x]);
49 }
