Compute Effective Letter Permissions in a DAG

Company: Snowflake

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Technical Screen

Overview: Compute effective letter permissions for every node in a directed acyclic graph where allowed letters propagate through all ancestors but disallow settings remain local. The task requires deterministic alphabetical permission strings and lexical node ordering while handling multiple parents and transitive inheritance.

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