leetcode

Diameter of Binary Tree

Diameter of Binary Tree

DFS 版本 - 64ms

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def diameterOfBinaryTree(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        self.length = 0
        
        def depth(node):
            if not node: return 0
            left = depth(node.left)
            right = depth(node.right)
            self.length = max(self.length, left + right)
            return 1 + max(left, right)
        
        depth(root)
        return self.length

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