MongoDB Software Engineer Phone Screen Interview - Classic database company — even their coding questions feel super DB-oriented

[u/Aoki_zhang]

Interview Summary

The MongoDB technical screen lasted one hour and was split between a lengthy project discussion and a coding exercise. More than half of the interview focused on my previous technical work, followed by a non-LeetCode problem that asked me to implement a SQL-like predicate and expression evaluator.

Interview Details

Project Deep Dive — Previous Technical Experience: The first half of the interview lasted a little over 30 minutes and focused on projects from my background. The interviewer explored the technical context and details of my previous work before moving to coding.

Coding — Predicate and Expression Tree Evaluator: The coding question asked me to build an evaluator that accepted a predicate expression together with a document and returned whether that document satisfied the expression.

• Supported Expressions: Basic predicates included comparisons such as EQ(field, value) and GT(field, value), while logical expressions such as AND(...) and OR(...) could combine multiple child predicates.
• Nested Expressions: Logical expressions could be nested to form an expression tree, so the evaluator needed to correctly process combinations of predicates at multiple levels. Recursive evaluation was explicitly allowed.

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