1026. Maximum Difference Between Node and Ancestor

https://leetcode.com/problems/maximum-difference-between-node-and-ancestor

Description

Given the root of a binary tree, find the maximum value v for which there exist different nodes a and b where v = |a.val - b.val| and a is an ancestor of b.

A node a is an ancestor of b if either: any child of a is equal to b or any child of a is an ancestor of b.

Example 1:

**Input:** root = [8,3,10,1,6,null,14,null,null,4,7,13]
**Output:** 7
**Explanation:** We have various ancestor-node differences, some of which are given below :
|8 - 3| = 5
|3 - 7| = 4
|8 - 1| = 7
|10 - 13| = 3
Among all possible differences, the maximum value of 7 is obtained by |8 - 1| = 7.

Example 2:

**Input:** root = [1,null,2,null,0,3]
**Output:** 3

Constraints:

• The number of nodes in the tree is in the range [2, 5000].

• 0 <= Node.val <= 105

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