clone-graph

1. clone-graph

Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.

思路：dfs，其实就是递归。

/**
 * 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];
    }
};