Top K Frequent Words / Characters

Phone ScreenRobinhoodLast reported July 2026Low Frequency

Reported: 3× across candidate reports
First seen: April 2025
Last reported: July 2026
Reported outcome: mixed

Problem Overview

Given a string (ranging from a short sentence to an entire book paragraph), extract all words, count their frequencies, and return the top K most frequent words along with their counts. Requirements: (1) case-insensitive — normalize all words to lowercase; (2) punctuation and whitespace are delimiters, not part of words;…

4 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
The rest of the problem statement — full requirements, constraints, and edge cases
Approach and trade-offs — what passing candidates did, and the mistakes that sink people

Unlock the full Robinhood catalog

Full problem statements, candidate-reported follow-ups, and walkthroughs — for every Robinhood question.

Unlock with Pro

Already a member? Sign in

Verified Source

Every question is reconstructed from multiple independent candidate reports. Verbatim follow-ups, not invented ones.

Codex Fact-Checked

Technical claims, formulas, and scale numbers are reviewed against primary sources.

Interviewer Follow-ups

The exact follow-ups reported by candidates, with the trigger that prompts each one — plus the mistakes that sink people.