[LeetCode]Clone Graph

Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.

OJ's undirected graph serialization:

Nodes are labeled uniquely.

We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.

As an example, consider the serialized graph {0,1,2#1,2#2,2}.

The graph has a total of three nodes, and therefore contains three parts as separated by #.

1. First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
2. Second node is labeled as 1. Connect node 1 to node 2.
3. Third node is labeled as 2. Connect node 2 to node 2 (itself), thus forming a self-cycle.import java.util.ArrayList;

   import java.util.ArrayList;import java.util.HashMap;import java.util.LinkedList;import java.util.List;import java.util.Queue;  class UndirectedGraphNode {      int label;      List<UndirectedGraphNode> neighbors;      UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }  };public class Solution {    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {    if(node==null) return null;    Queue<UndirectedGraphNode> queue=new LinkedList<UndirectedGraphNode>();    HashMap<UndirectedGraphNode,UndirectedGraphNode> map=new HashMap<UndirectedGraphNode,UndirectedGraphNode>();    UndirectedGraphNode newGraph=new UndirectedGraphNode(node.label);    map.put(node, newGraph);    queue.add(node);    while(!queue.isEmpty()){    UndirectedGraphNode n=queue.poll();    UndirectedGraphNode clone=map.get(n);    for(UndirectedGraphNode nn:n.neighbors){    if(!map.containsKey(nn)){    UndirectedGraphNode temp=new UndirectedGraphNode(nn.label);    map.put(nn, temp);    queue.add(nn);    }    clone.neighbors.add(map.get(nn));    }    }    return newGraph;    }}