LeetCode Q133: 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 #.

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
      / \
     /   \
    0 --- 2
         / \
         \_/

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

view raw Q133CloneGraph.cpp hosted with ❤ by GitHub