Validate a Bijective Substitution Cipher

Company: Remitly

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Onsite

Overview: Determine whether two printable-ASCII strings define a valid bijective character substitution. This coding interview problem tests consistent forward and reverse mappings, repeated characters, collisions, length mismatches, and linear-time reasoning across whitespace and punctuation.