[LeetCode]题解（python）：133-Clone Graph

# Definition for a undirected graph node
# class UndirectedGraphNode(object):
#     def __init__(self, x):
#         self.label = x
#         self.neighbors = []

class Solution(object):
    def cloneGraph(self, node):
        """
        :type node: UndirectedGraphNode
        :rtype: UndirectedGraphNode
        """
        if node == None:
            return node
        d  = {}
        def dfs(n):
            if n in d:
                return d[n]
            ans = UndirectedGraphNode(n.label)
            d[n] = ans
            for i in n.neighbors:
                ans.neighbors.append(dfs(i))
            return ans
        return dfs(node)