Trade Reconciliation: Find Unmatched Buy/Sell Trades

Phone ScreenCitadelLast reported September 2026Low Frequency

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

Problem Overview

You are given a pile of trade data. Return the trades that cannot be paired: buys and sells that do not match up. In other words, reconcile the trades and find the breaks. The report gives no data format, pairing rule or function signature: you settle them with the interviewer,…

1 candidate-reported follow-up — 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.