leetcode[133]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:

UndirectedGraphNode * clone(unordered_map<int, UndirectedGraphNode *> &map1,UndirectedGraphNode *node)

{

    if(map1.count(node->label))

        return map1[node->label];

    UndirectedGraphNode *new_node=new UndirectedGraphNode(node->label);

    map1[new_node->label]=new_node;

    for(auto &nod :node->neighbors)

    {

        new_node->neighbors.push_back(clone(map1,nod));

    }

    return new_node;

}

    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {

        if(node==NULL)return node;

        unordered_map<int, UndirectedGraphNode *> map1;

        return clone(map1,node);

    }

};