leetcode-133-克隆图

题目描述：

 

方法一：dfs+hashmap

"""
# Definition for a Node.
class Node:
    def __init__(self, val, neighbors):
        self.val = val
        self.neighbors = neighbors
"""

class Solution:

    def cloneGraph(self, node: 'Node') -> 'Node':

        if not node:

            return node

        dic = {}

        def dfs(node):

            if node not in dic:

                dic[node] = Node(node.val,[])

                for i in node.neighbors:

                    dic[node].neighbors.append(dfs(i))

            return dic[node]

        dfs(node)

        return dic[node]

 方法二：

class Solution:
    def cloneGraph(self, node: 'Node') -> 'Node':
        return copy.deepcopy(node)

 方法三：bfs

class Solution:

    def cloneGraph(self, node: 'Node') -> 'Node':

        if not node:

            return 

        queue = collections.deque()

        queue.append(node)

        visited = {}

        visited[node] = Node(node.val, [])

        while queue:

            tmp = queue.popleft()

            for i in tmp.neighbors:

                if i not in visited:

                    visited[i] = Node(i.val,[])

                    queue.append(i)

                visited[tmp].neighbors.append(visited[i])

        return visited[node]