leetcode------Clone Graph

标题：	Clone Graph
通过率：	23.7%
难度：	中等

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

         / \

         \_/

 

 

本题这样出没有什么意义，上面解释一堆再代码里面根本没有显示，直接出图的遍历顺序会好一点。直接看代码

 1 # Definition for a undirected graph node

 2 # class UndirectedGraphNode:

 3 #     def __init__(self, x):

 4 #         self.label = x

 5 #         self.neighbors = []

 6 

 7 class Solution:

 8     # @param node, a undirected graph node

 9     # @return a undirected graph node

10     def cloneGraph(self, node):

11         if node == None: return None

12         nodeMap={}

13         return self.cloneNode(node,nodeMap)

14     

15     

16     def cloneNode(self,node,nodeMap):

17         if node == None:return None

18         if nodeMap.has_key(node):

19             return nodeMap[node]

20         else :

21             clone =UndirectedGraphNode(node.label)

22             nodeMap[node]=clone

23             for nei in node.neighbors:

24                 clone.neighbors.append(self.cloneNode(nei,nodeMap))

25         return clone