Code Room
CodingHardcod-g1081
Subject Query predicate evaluatorLevel Mid–Senior~30 minCommon in Databases & SQL · Algorithms & data structures interviewsIndustries Software development

Question

Evaluate a WHERE-clause predicate tree against rows. A predicate node is either a comparison ['cmp', col, op, value] with op in '=','!=','>','<','>=','<=', or a boolean ['and', child1, child2, ...] / ['or', child1, child2, ...] / ['not', child]. Given rows (list of dicts) and one predicate, return the list of rows (in input order) for which the predicate evaluates to true. Comparisons use Python's natural ordering on the stored values. 'and' of zero children is true; 'or' of zero children is false.

Implement
filter_rows(rows: list[dict], pred: list) → list[dict]
Examples
in[[{"a":1,"b":10},{"a":2,"b":5},{"a":3,"b":20}],["and",["cmp","a",">",1],["cmp","b",">=",10]]]out[{"a":3,"b":20}]
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.