Given the root
of a binary tree, return the length of the diameter of the tree.
The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root
.
The length of a path between two nodes is represented by the number of edges between them.
Example 1:
1
/ \
2 3
/ \
4 5
Input: root = [1,2,3,4,5]
Output: 3
Explanation: 3 is the length of the path [4,2,1,3] or [5,2,1,3].
Example 2:
Input: root = [1,2]
Output: 1
Constraints:
 The number of nodes in the tree is in the range
[1, 10^{4}]
.
100 <= Node.val <= 100
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# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def __init__(self):
self.max_diameter = 1
def longest_path(self, root: Optional[TreeNode]) > int:
if not root:
return 0
left_path = self.longest_path(root.left)
right_path = self.longest_path(root.right)
self.max_diameter = max(self.max_diameter, left_path + right_path)
return max(left_path, right_path) + 1
def diameterOfBinaryTree(self, root: Optional[TreeNode]) > int:
self.longest_path(root)
return self.max_diameter
