algomap/diameter_of_binary_tree.py at main · djholty/algomap · GitHub

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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 diameterOfBinaryTree(self, root: Optional[TreeNode]) -> int:

        largestdiam = 0

        def height(root):
            if not root:
                return 0
            nonlocal largestdiam
            leftheight = height(root.left)
            rightheight = height(root.right)

            diameter = leftheight + rightheight
            largestdiam = max(largestdiam, diameter)
            return 1 + max(leftheight,rightheight)
        height(root)
        return largestdiam

"""
543. Diameter of Binary Tree
Solved
Easy
Topics
Companies

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:

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, 104].
    -100 <= Node.val <= 100

"""