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.

Visually, the graph looks like the following:

       1
      / \
     /   \
    0 --- 2
         / \
         \_/

Have you met this question in a real interview? 

public class Solution {

    /**

     * @param node: A undirected graph node

     * @return: A undirected graph node

     */

    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {

        // write your code here

        if(node == null) return null;

        HashMap<UndirectedGraphNode, UndirectedGraphNode> map = new HashMap<UndirectedGraphNode, UndirectedGraphNode>();

        Queue<UndirectedGraphNode> queue = new LinkedList<UndirectedGraphNode>();

        queue.offer(node);

        UndirectedGraphNode newNode = new UndirectedGraphNode(node.label);

        map.put(node, newNode);

        while(!queue.isEmpty()){

            UndirectedGraphNode cur = queue.poll();

            ArrayList<UndirectedGraphNode> neighbors = cur.neighbors;

            for(UndirectedGraphNode n : neighbors){

                if(map.containsKey(n)){

                    map.get(cur).neighbors.add(map.get(n));

                } else {

                    UndirectedGraphNode temp = new UndirectedGraphNode(n.label);

                    map.put(n, temp);

                    map.get(cur).neighbors.add(temp);

                    queue.offer(n);

                }

                

            }

            

        }

        return newNode;

    }

    

   

}

Yes