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         / \         \_/

题意：实现结构体的复制。

思路：借助map对复制过的元素做记录，以免重复复制。

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