Google 2026 New Grad R1 Rejection: Mode of a Ternary Search Tree

Role: Software Engineer, New Grad
Result: Rejected after R1
Report time: December 2025

Coding: mode of a ternary search tree

The tree follows these ordering rules:

• left.value < node.value
• middle.value == node.value
• right.value > node.value

Return the mode: the value that appears most frequently in the tree.

The candidate and interviewer discussed edge cases, and the candidate believed the implementation already covered them.

Practice: Mode of a Ternary Search Tree

Follow-up: broken tree

The interviewer asked about a “broken tree,” but the source does not define which invariant is violated, how that input is represented, or what output is required. Comments asked whether a HashMap was needed and whether the task could be solved without one, but the candidate did not provide further clarification.