Solution: Lowest Common Ancestor of a Binary Tree

Explore how to determine the lowest common ancestor of two nodes in a binary tree with depth-first search. Understand the recursive approach that checks left and right subtrees, tracks nodes found, and identifies the common ancestor efficiently. Learn the time and space complexity involved and a concise optimization to improve recursion calls.

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Statement
Solution

Statement

Given the root node of a binary tree with $n$ nodes, your task is to find the lowest common ancestor of two of its nodes, p and q.

Note: The lowest common ancestor of two nodes, p and q, is defined as the lowest node in the binary tree that has both p and q as descendants.

A node can also be a descendant of itself. For example, if q is a descendant of p, and we know that p is a descendant of itself, then p will be the lowest common ancestor of p and q.

Constraints:

$2 \leq n \leq 500$

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