[leetcode]Clone Graph

/**
* Definition for undirected graph.
* struct UndirectedGraphNode {
*     int label;
*     vector<UndirectedGraphNode *> neighbors;
*     UndirectedGraphNode(int x) : label(x) {};
* };
*/
class Solution {
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
if( node == nullptr ) return nullptr;
unordered_map<UndirectedGraphNode * , UndirectedGraphNode *> otn;
otn[node] = new UndirectedGraphNode(node -> label);
queue<UndirectedGraphNode *> que;
que.push(node);

while(!que.empty()){
UndirectedGraphNode* node = que.front() ; que.pop();
int size = node -> neighbors.size();

for(int i = 0 ; i < size ; i ++){
if(otn.find(node -> neighbors[i]) == otn.end()){
UndirectedGraphNode * tmp = new UndirectedGraphNode(node -> neighbors[i] -> label);
otn[node] -> neighbors.push_back(tmp);
otn[node -> neighbors[i]] = tmp;
que.push(node -> neighbors[i]);
}else{
otn[node] -> neighbors.push_back(otn[node -> neighbors[i]]);
}
}
}
return otn[node];
}
};