1.union
2.查

//节点定义
public static class Node {
        // whatever you like
    }

//主要类
public static class DisjointSets {
        //(key,value)表示，key的父节点，是value,(Data_A,Data_B)代表，Data_A的父节点是Data_B
        public HashMap<Node, Node> fatherMap;
        //Node为代表节点，Integer为元素的个数，若Node不为代表节点，Integer为无用
        public HashMap<Node, Integer> rankMap   ;

        public DisjointSets() {
            fatherMap = new HashMap<Node, Node>();
            rankMap = new HashMap<Node, Integer>();
        }

        public void makeSets(List<Node> nodes) {
            fatherMap.clear();
            rankMap.clear();
            for (Node node : nodes) {
                fatherMap.put(node, node);
                rankMap.put(node, 1);
            }
        }


        //找代表的过程
        public Node findFather(Node n) {
            Node father = fatherMap.get(n);
            if (father != n) {
                father = findFather(father);
            }
            fatherMap.put(n, father);
            return father;
        }


        //是否属于同一个集合
        public boolean isSameSet(Node a,Node b){
            return findFather(a) == findFather(b);
        }
        
        
            
        public void union(Node a, Node b) {
            if (a == null || b == null) {
                return;
            }
            Node aFather = findFather(a);
            Node bFather = findFather(b);
            if (aFather != bFather) {
                int aFrank = rankMap.get(aFather);
                int bFrank = rankMap.get(bFather);
                if (aFrank <= bFrank) {
                    fatherMap.put(aFather, bFather);
                    rankMap.put(bFather, aFrank + bFrank);
                } else {
                    fatherMap.put(bFather, aFather);
                    rankMap.put(aFather, aFrank + bFrank);
                }
            }
        }

    }