Problem context and objectives
Mission briefing
Archive pathfinder · Clues branch through a living archive
Explore only the branches that can still contain the answer: The Closest Grove.
Ignoring the parent-child rule turns a focused search into a full maze traversal.
How you win
- 1Recognize when Closest BST value matches the clues
- 2Keep this true after every move: closest is the best value on the unique root-to-search-position path
- 3Reach the result within O(height) time and O(1) space
Rules and pressure
- Target cost: O(height) time and O(1) space
- State rule: closest is the best value on the unique root-to-search-position path
Lesson 1 of 3
Choose the best candidate and one BST direction at every path node. Break distance ties toward the smaller value. Lesson questions refer to the original example.
Decide both candidate and direction at every node to understand one-path search.
Your call · With target 3.714 at root 4, which direction remains useful?