R2-图

目录

DFS

BFS

​ps:

 图遍历即可，使用字典来记录访问过的结点。

DFS

"""
# Definition for a Node.
class Node:
    def __init__(self, val = 0, neighbors = None):
        self.val = val
        self.neighbors = neighbors if neighbors is not None else []
"""

from typing import Optional
class Solution:
    def cloneGraph(self, node: Optional['Node']) -> Optional['Node']:
        #遍历整个图即可，已经访问的点，使用一个字典来记录
        #DFS
        look={}
        def dfs(node):
            if not node:
                return
            if node in look:
                return look[node]
            clone=Node(node.val,[])
            look[node]=clone
            for n in node.neighbors:
                clone.neighbors.append(dfs(n))
            return clone
        return dfs(node)


        

 

BFS

"""
# Definition for a Node.
class Node:
    def __init__(self, val = 0, neighbors = None):
        self.val = val
        self.neighbors = neighbors if neighbors is not None else []
"""

from typing import Optional
class Solution:
    def cloneGraph(self, node: Optional['Node']) -> Optional['Node']:
        #遍历整个图即可，已经访问的点，使用一个字典来记录
        #BFS
        look={}
        def bfs(node):
            if not node:
                return
            clone=Node(node.val,[])
            look[node]=clone
            queue=deque()
            queue.appendleft(node)
            while queue:
                tmp=queue.pop()
                for n in tmp.neighbors:
                   if n not in look:
                      look[n]=Node(n.val,[])
                      queue.appendleft(n)
                   look[tmp].neighbors.append(look[n])
            return clone
        return bfs(node)


        

 ps:

很ok啊DFS和BFS