BlackRock·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

Jul 2026

Summary

Went through a logic-based scheduling puzzle for a Software Engineer role at BlackRock. Not a traditional coding round, more like a constraint-satisfaction problem dressed up as an interview question. Felt a bit thrown off at first but worked through it systematically.

Questions Asked (1)

Three candidates are each assigned to one of three consecutive days. Given a set of ordering and exclusion constraints, determine which candidate interviews on which day and explain your reasoning.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

I stared at this for a second because it felt more like a logic puzzle than a software question.

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AI HintsAI Generated

Suggested Approach

Treat the problem as a constraint satisfaction problem: define variables for each candidate's day, translate each constraint into a logical relation, then systematically eliminate possibilities. Use a small example or truth table to verify your deductions, and clearly explain each step of your reasoning.

Pro tip: Before diving into constraints, restate the problem in your own words and confirm your understanding with the interviewer—this avoids solving the wrong problem and shows structured thinking.

1. Clarify and Define

Restate the problem, confirm the number of candidates and days, and list all constraints explicitly. Define variables (e.g., C1, C2, C3 for candidates; D1, D2, D3 for days).

2. Translate Constraints

Convert each ordering or exclusion constraint into a formal logical statement (e.g., 'A before B' means day(A) < day(B); 'C not on day 2' means day(C) ≠ 2).

3. Systematic Elimination

Start with the most restrictive constraint and branch out. Use a table or grid to track possible assignments, eliminating options that violate any constraint.

4. Verify and Explain

Check that the final assignment satisfies all constraints. Walk through your reasoning step-by-step, highlighting key deductions and why alternatives were ruled out.

Key Points to Mention

Constraint satisfaction problem (CSP) formulation
Logical deduction and elimination techniques
Use of truth tables or grids for clarity
Systematic search vs. brute force
Verification of the solution against all constraints
Communication of reasoning to the interviewer

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