Sig·Software Engineer·Technical Phone Screen·Junior

Junior

Apr 2026

Summary

SIG quant researcher interview, got hit with a logic puzzle about cats and truth-telling rules. Pretty classic SIG flavor, the kind of thing where you either see the structure fast or you're just spinning.

Questions Asked (1)

Asta, Bronya, and Clara each own a different number of cats. The rule is: if you're talking to someone with fewer cats than you, you tell the truth; if they have more, you lie. Given their conversation, figure out how many cats Clara has.

Algorithms & Data Structures

Author's notes

This type of puzzle wrecked me the first time I saw something like it.

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AI HintsAI Generated

Suggested Approach

First, clarify the rules and the exact conversation statements, then model the problem as a constraint satisfaction puzzle over the six possible orderings of cat counts. Systematically test each ordering against the truth/lie condition to find which assignments are consistent, and deduce Clara's count.

Pro tip: State your assumptions explicitly and walk through one example ordering to show your reasoning process. This demonstrates structured thinking and makes it easy for the interviewer to follow and correct you if needed.

1. Clarify the problem

Restate the rules and the conversation to ensure you understand who said what and the exact condition for truth/lie. Ask clarifying questions if any part is ambiguous.

2. Define variables and constraints

Let the number of cats for Asta, Bronya, and Clara be distinct integers. Translate each statement into a logical condition based on the relative cat counts.

3. Enumerate possible orderings

List all 3! = 6 possible strict orderings of their cat counts. For each ordering, determine the truth value of each statement according to the rule.

4. Eliminate inconsistent orderings

Check which orderings make all statements consistent with the truth/lie rule. Discard any ordering that leads to a contradiction.

5. Deduce Clara's count

From the remaining consistent ordering(s), determine Clara's relative position and thus her number of cats. If multiple solutions exist, explain why and what additional information would disambiguate.

Key Points to Mention

The rule depends on the listener's cat count relative to the speaker's, not the speaker's alone.
Each person has a different number of cats, so the ordering is strict.
Truth/lie status is determined per statement based on the comparison.
Systematic enumeration of all possible orderings ensures no solution is missed.
Contradictions arise when a statement's truth value conflicts with the rule.
If multiple solutions exist, the problem may be underdetermined; state that clearly.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.