Union-Find / Disjoint Set Union Template

CodingRobinhoodLast reported April 2026Low Frequency

Reported: 1× across candidate reports
First seen: April 2026
Last reported: April 2026
Reported outcome: unknown

Problem Overview

Implement a standard Union-Find (Disjoint Set Union, DSU) data structure. The problem is described as the most fundamental DSU template question — implement the core operations: find…

2 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

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Verified Source

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

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Interviewer Follow-ups

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