kruskal算法 源码（java）

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/**
 * 
 * kruskal算法 适用范围：要求无向图
 *
 */
//undirected graph only
public class Code_04_Kruskal {

	// Union-Find Set
	public static class UnionFind {
		private HashMap<Node, Node> fatherMap;
		private HashMap<Node, Integer> rankMap;

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

		private Node findFather(Node n) {
			Node father = (n);
			if (father != n) {
				father = findFather(father);
			}
			(n, father);
			return father;
		}

		public void makeSets(Collection<Node> nodes) {
			();
			();
			for (Node node : nodes) {
				(node, node);
				(node, 1);
			}
		}

		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 = (aFather);
				int bFrank = (bFather);
				if (aFrank <= bFrank) {
					(aFather, bFather);
					(bFather, aFrank + bFrank);
				} else {
					(bFather, aFather);
					(aFather, aFrank + bFrank);
				}
			}
		}
	}

	public static class EdgeComparator implements Comparator<Edge> {

		@Override
		public int compare(Edge o1, Edge o2) {
			return  - ;
		}

	}

	public static Set<Edge> kruskalMST(Graph graph) {
		UnionFind unionFind = new UnionFind();//生成一个并查集
		(());
		//生成一个优先级队列（堆）
		PriorityQueue<Edge> priorityQueue = new PriorityQueue<>(new EdgeComparator());
		for (Edge edge : ) {
			(edge);
		}
		Set<Edge> result = new HashSet<>();
		while (!()) {
			Edge edge = ();
			if (!(, )) {
				(edge);
				(, );
			}
		}
		return result;
	}
}