Question
A tag browser shows an A-to-Z index, and each letter heading displays how many tags live under it. Given a list of lowercase, non-empty tag strings (repeats allowed and counted separately), group the tags by their first letter and return a dictionary that maps each first letter (as a one-character string) to the number of tags starting with that letter. Letters with no tags must not appear in the result. For example, ["rock", "rap", "pop"] gives {"r": 2, "p": 1}.
tags_by_initial(tags: list[str]) → dict[str,int][["rock","rap","pop"]]out{"p":1,"r":2}State 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.