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LeetCode 543 Diameter Of Binary Tree - Easy

543. Diameter of Binary Tree -- Easy

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543. Diameter Of Binary Tree — Easy

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Problem

  1. Diameter of Binary Tree -- Easy

Given a binary tree, you need to compute 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.

Example: Given a binary tree 1 /
2 3 / \
4 5
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].

Note: The length of path between two nodes is represented by the number of edges between them.

Solution

# 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: TreeNode) -> int:
        self.res = 0
        self.dfs(root)
        return self.res
    def dfs(self, node):
        if not node:
            return 0
        left = self.dfs(node.left)
        right = self.dfs(node.right)
        self.res = max(self.res, left + right)
        return max(left, right) + 1

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