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
         / \
         \_/

/*struct UndirectedGraphNode {
    int label;
    vector<UndirectedGraphNode *> neighbors;
    UndirectedGraphNode(int x) : label(x) {};
};*/

class Solution {
public:
    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(node == NULL) return NULL;
        map<UndirectedGraphNode*,UndirectedGraphNode*> map0;
        queue<UndirectedGraphNode*> queue0;
     
        UndirectedGraphNode *ret = new UndirectedGraphNode(node->label),*p = ret;
		map<UndirectedGraphNode *,UndirectedGraphNode*>::iterator it ;
		map0[node] = ret;
        queue0.push(node);
        
        while(!queue0.empty())
        {
            node = queue0.front();
            queue0.pop();
			p = map0[node];
            for(int i = 0;i<node->neighbors.size();i++)
            {
                it = map0.find(node->neighbors[i]);
                if(it == map0.end()){
                    UndirectedGraphNode *cur = new UndirectedGraphNode(node->neighbors[i]->label);
                    map0[node->neighbors[i]] = cur;
                    p->neighbors.push_back(cur);
                    queue0.push(node->neighbors[i]);
                }else{
                    p->neighbors.push_back(it->second);
                }      
            }
        }
        return ret; 
    }
};

252 ms