Represent and Evaluate Boolean Predicate Expressions
Company: Coreweave
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Onsite
Design a data structure to represent and evaluate predicates such as `abc > 5 and (test < 8 or team > 9)`. Support comparisons, `and`, `or`, parentheses, and evaluation against a dictionary of variable values.
### Constraints & Assumptions
- Variables map to numeric values.
- Operators include `<`, `>`, `<=`, `>=`, `==`, `and`, and `or`.
- Input can be parsed before evaluation.
- Short-circuit evaluation is desirable.
### Clarifying Questions to Ask
- Do we need `not`?
- Are strings or only numbers supported?
- Should unknown variables be errors or false?
- Does the parser need to handle whitespace and precedence?
- Will predicates be reused many times?
### What a Strong Answer Covers
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### Follow-up Questions
- How would you add function calls?
- How would you compile predicates for faster repeated evaluation?
- How would you serialize the AST?
- How would you prevent unsafe arbitrary code execution?
Quick Answer: This Coreweave software engineering question asks candidates to represent and evaluate boolean predicate expressions. It is useful practice for expression trees, recursive evaluation, short-circuit behavior, and designing extensible internal representations.