{"id":"guard-clause-then-expression-pattern","text":"Easy-difficulty solutions follow a guard-clause-then-expression pattern: validate the input constraint up front, then return the entire transformation as a single expression.","truth_value":"IN","source":"entries/2026/06/06/convert-1d-array-into-2d-array-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"guard-clause-then-expression-pattern","truth_value":"IN","reason":"premise"}]}}