Closest BST Value | Dataford Interview Questions

Closest Binary Search Tree Value (LC 270)

Asked in the coding 2 stage. Given a binary search tree and a numeric target, return the value in the tree closest to the target. If two values are equally close, return the smaller value. Reported follow-up: Would anything change if node values were float?

Input and Output

The function receives root, represented as [value, left, right], with null for an empty child, and target. Return the closest numeric node value.

Constraints

The tree is a valid BST with 1 to 10,000 nodes
Node values and target are integers or floats
Node values are unique
The input tree is represented as [value, left, right], with null for an empty child

Function Signature

def closest_value(root, target):

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Problem