LeetCode559. Maximum Depth of N-ary Tree

Posted 2021-01-28

?????????root   maximum   alt   span   roo   ??????   ??????   pen   nod   

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"""
# Definition for a Node.
class Node(object):
    def __init__(self, val, children):
        self.val = val
        self.children = children
"""
class Solution(object):
    def maxDepth(self, root):
        """
        :type root: Node
        :rtype: int
        """
        if not root:
            return 0
        if not root.children:
            return 1
        sub_max=[]
        for child in root.children:
            sub_max.append(self.maxDepth(child)+1) 
        return max(sub_max)

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   1.???list????????????None??????[ ]?????????????????? if not list

   2.list ??????????????????append

  3.list?????????max

 

 

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class Solution(object):
    def maxDepth(self, root):
        """
        :type root: Node
        :rtype: int
        """
        if not root:
            return 0
        if not root.children:
            return 1
        depth = 1 + max(self.maxDepth(child) for child in root.children)
        return depth

????????????list????????????

 

"""
# Definition for a Node.
class Node(object):
    def __init__(self, val, children):
        self.val = val
        self.children = children
"""
class Solution(object):
    def maxDepth(self, root):
        """
        :type root: Node
        :rtype: int
        """
        if not root: return 0
        depth = 0
        que = collections.deque()
        que.append(root)
        while que:
            size = len(que)
            for i in range(size):
                node = que.popleft()
                for child in node.children:
                    que.append(child)
            depth += 1
        return depth

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