Coding (Algo)

Find the First Unrepeated Event

Algorithm: Hash map Difficulty: Easy Time: 25 minutes

Goal

Return the first event value that occurs exactly once across the complete input stream.

What this task practices

Find the First Unrepeated Event is a coding (algo) interview exercise that trains prompt interpretation, explicit assumptions, a concrete response, and a clear explanation of tradeoffs. The catalog marks it as easy difficulty. It focuses on Technical Reasoning, Testing, Validation. The signed-in workspace provides the tools for the round and evaluates the attempt against task-specific criteria. Reference solutions, hidden checks, evaluator instructions, and candidate work remain private.