[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

#

.

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
/ \
\_/

/**
* Definition for undirected graph.
* struct UndirectedGraphNode {
*     int label;
*     vector<UndirectedGraphNode *> neighbors;
*     UndirectedGraphNode(int x) : label(x) {};
* };
*/
class Solution {
private:
map<int,UndirectedGraphNode *> m;
public:
UndirectedGraphNode *DFS(UndirectedGraphNode *node)
{
if(node==NULL) return NULL;
if(m.find(node->label)!=m.end()) return m[node->label];
UndirectedGraphNode *newNode=new UndirectedGraphNode(node->label);
m[newNode->label]=newNode;
for(vector<UndirectedGraphNode *>::iterator it=node->neighbors.begin();it!=node->neighbors.end();it++)
{
UndirectedGraphNode *newNeighbor=DFS(*it);
newNode->neighbors.push_back(newNeighbor);
}
return newNode;
}
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
return DFS(node);
}
};