找出无向图汇总的相连要素find-the-connected-component-in-the-undirected-graph

 1 /**
 2  * Definition for Undirected graph.
 3  * class UndirectedGraphNode {
 4  *     int label;
 5  *     ArrayList<UndirectedGraphNode> neighbors;
 6  *     UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }
 7  * };
 8  */
 9 public class Solution {
10     /**
11      * @param nodes a array of Undirected graph node
12      * @return a connected set of a Undirected graph
13      */
14     public List<List<Integer>> connectedSet(ArrayList<UndirectedGraphNode> nodes) {
15         // Write your code here
16         int m = nodes.size();
17         Map<UndirectedGraphNode,Boolean> visited = new HashMap<>();
18         for(UndirectedGraphNode node:nodes){
19             visited.put(node,false);
20         }
21         List<List<Integer>> result = new ArrayList<>();
22         for(UndirectedGraphNode node:nodes){
23             if(visited.get(node) == false){
24                 bfs(node,visited,result);
25             }
26         }
27         return result;
28     }
29     public void bfs(UndirectedGraphNode node,Map<UndirectedGraphNode,Boolean> visited,List<List<Integer>> result){
30         List<Integer> row = new ArrayList<>();
31         Queue<UndirectedGraphNode> queue = new LinkedList<>();
32         visited.put(node,true);
33         queue.offer(node);
34         while(!queue.isEmpty()){
35             UndirectedGraphNode u = queue.poll();
36             row.add(u.label);
37             for(UndirectedGraphNode v:u.neighbors){
38                 if(visited.get(v)==false){
39                     visited.put(v,true);
40                     queue.offer(v);
41                 }
42             }
43         }
44         Collections.sort(row);
45         result.add(row);
46     }
47 }