Count Valid Infection Orders

Company: Uber

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Onsite

Quick Answer: This question evaluates combinatorial enumeration and algorithmic reasoning by counting valid sequences of state changes in a linear infection process. It is commonly asked in technical interviews because it measures the ability to model propagation constraints, count permutations under adjacency restrictions, and implement efficient solutions within the Coding & Algorithms domain, focusing on practical application rather than purely conceptual understanding.