Implement factorial and square list
Company: Morgan Stanley
Role: Data Scientist
Category: Coding & Algorithms
Difficulty: medium
Interview Round: HR Screen
Implement two Python functions:
1. `factorial(n)`: return `n!` for a non-negative integer `n`. First write an iterative version. Be ready to discuss how a recursive version would differ.
2. `squares(n)`: given a non-negative integer `n`, return the squares of the first `n` integers in order. For example, `n = 5` should return `[0, 1, 4, 9, 16]`.
Discuss time and space complexity, input validation, and edge cases such as `n = 0`.
Quick Answer: This question evaluates implementation skills for basic algorithms—computing factorial iteratively and generating a sequence of squares—along with understanding of recursion versus iteration, input validation, and analysis of time and space complexity.