Question
A happy number is defined by repeatedly replacing the number with the sum of the squares of its digits; if this process eventually reaches 1 the number is happy, otherwise it loops forever in a cycle that never includes 1. Given a positive integer n (1 <= n <= 2^31 - 1), return True if n is happy and False otherwise. For example 19 -> 1+81+1+81 ... -> 1, so 19 is happy.
is_happy_number(n: int) → bool[19]outtrueState your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.