Buy and Sell Stock: I → II → k Transactions (DP)

CodingCitadelLast reported May 2026Low Frequency
Reported
3× across candidate reports
First seen
January 2026
Last reported
May 2026
Reported outcome
mixed

Problem Overview

You are given prices, where prices[i] is the price of one stock on day i. You may hold at most one share at a time, and you must buy before you sell. The round is one problem that the interviewer escalates in three graded parts, each asked after you finish…

  • 7 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.
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.
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