LeetCode 0133 - Clone Graph

Desicription

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
2
3
4
5
6
1
/ \
/ \
0 --- 2
/ \
\_/

Solution

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/**
* Definition for undirected graph.
* struct UndirectedGraphNode {
* int label;
* vector<UndirectedGraphNode *> neighbors;
* UndirectedGraphNode(int x) : label(x) {};
* };
*/
class Solution {
private:
unordered_map<UndirectedGraphNode*, UndirectedGraphNode*> mp;
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
if(node == NULL)
return NULL;
if(mp.find(node) == mp.end()) {
mp[node] = new UndirectedGraphNode(node->label);
for(auto it : node->neighbors) {
mp[node]->neighbors.push_back(cloneGraph(it));
}
}
return mp[node];
}
};