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 #.

First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
Second node is labeled as 1. Connect node 1 to node 2.
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
         / 
         \_/
思路：
思路类似上题，用一个map来保存新旧graph节点的对应关系
代码：

 1     UndirectedGraphNode *clone(UndirectedGraphNode *node, map<int,UndirectedGraphNode*> &table)
 2     {
 3         if(node==NULL)
 4             return NULL;
 5             
 6         if(table.find(node->label)!=table.end())
 7             return table[node->label];
 8         
 9         UndirectedGraphNode *newnode=new UndirectedGraphNode(node->label);
10         table[newnode->label]=newnode;
11 
12         for(int i=0;i<node->neighbors.size();i++)
13         {
14             UndirectedGraphNode *neighbor=clone(node->neighbors[i],table);
15             newnode->neighbors.push_back(neighbor);
16         }
17         
18         return newnode;
19     }
20 
21     UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
22         // Note: The Solution object is instantiated only once and is reused by each test case.
23         //keep a hash table to check whether this node is visited or not
24         map<int,UndirectedGraphNode*> visitTable;
25         return clone(node,visitTable);
26     }