Section Recap

BST property: left < node < right for all nodes. Operations: Search, insert, delete all $O(h)$ where $h$ is height. Inorder traversal gives sorted order. Patterns:

• Validate by passing min/max bounds
• Successor: leftmost in right subtree
• Balance matters: worst case $O(n)$

Problems: Validate BST, kth smallest, LCA, recover BST.

Time: $O(h)$. Space: $O(h)$.