Trees: A Study Guide
Binary trees and BSTs: structure, traversals, operations and their Big-O, a Python traversal example, common pitfalls, and the days that cover trees.
Trees
Binary Tree Interview Questions: Patterns, Tips, and Solutions
A pattern-first guide to binary tree interview questions. Organizes tree problems into four families: traversal (DFS and BFS), recursive tree properties (depth, balance, sameness), BST-invariant problems (validation, kth smallest), and path problems (lowest common ancestor, max path sum), with full Python solutions, the recursive 'trust the subtree' mental model, complexity analysis, and links to the tree days of the 60-day curriculum.