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 {
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
queue<UndirectedGraphNode *> q;
set<UndirectedGraphNode *> s;
vector<UndirectedGraphNode *> v;
if(node == NULL) return NULL;
q.push(node);
v.push_back(node);
s.insert(node);
while(!q.empty())
{
UndirectedGraphNode *temp;
temp = q.front();
int n = temp->neighbors.size();
for(int i = 0; i < n; i++)
{
if(s.find(temp->neighbors[i]) == s.end())
{
q.push(temp->neighbors[i]);
v.push_back(temp->neighbors[i]);
s.insert(temp->neighbors[i]);
}
}
q.pop();
}

int n = v.size();
vector<int> nums;
vector<UndirectedGraphNode *> clone;
for(int i = 0; i < n; i++)
{
nums.push_back(v[i]->label);
v[i]->label = i;
UndirectedGraphNode *NewNode = new UndirectedGraphNode(i);
clone.push_back(NewNode);
}

for(int i = 0; i < n; i++)
{
int m = v[i]->neighbors.size();
for(int j = 0; j < m; j++)
{
int num = v[i]->neighbors[j]->label;
clone[i]->neighbors.push_back(clone[num]);
}
}

for(int i = 0; i < n; i++)clone[i]->label = nums[i];
return clone[0];
}
};