This problem set provides a comprehensive approach to mastering tree traversal techniques and binary search tree operations, focusing on fundamental and advanced topics. The collection covers essential tree traversal algorithms such as preorder, inorder, and postorder traversal, and extends into more complex topics like finding the lowest common ancestor (LCA), path sum problems, and binary tree properties like diameter and tilt. Additionally, it delves into the specific operations and properties of binary search trees (BST), including validation, search, deletion, and closest value retrieval.