-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathUnionFind3.java
More file actions
60 lines (46 loc) · 1.2 KB
/
UnionFind3.java
File metadata and controls
60 lines (46 loc) · 1.2 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
package union;
/**
* 基于size优化
*/
public class UnionFind3 implements UF{
private int[] parent;
private int[] sz; // sz[i]表示以i为根的集合中元素个数
public UnionFind3(int size){
parent = new int[size];
for (int i = 0; i < size; i++) {
parent[i] = i;
sz[i] = 1;
}
}
// p == parent[p] 是一个根节点
private int find(int p) {
if (p < 0 || p >= parent.length) {
throw new IllegalArgumentException("Index is illegal");
}
while (p != parent[p]) {
p = parent[p];
}
return p;
}
@Override
public int getSize() {
return parent.length;
}
@Override
public boolean isConnected(int p, int q) {
return find(p) == find(q);
}
@Override
public void unionElements(int p, int q) {
int pRoot = find(p);
int qRoot = find(q);
// 节点数少的根节点指向节节点数多的根节点
if (sz[pRoot] < sz[qRoot]){
parent[pRoot] = qRoot;
sz[qRoot] += sz[pRoot];
}else {
parent[qRoot] = pRoot;
sz[pRoot] += sz[qRoot];
}
}
}