Code RoomGroup tags by first letter
EasyPrep Room Coding #433

Group tags by first letter

CodingAlgorithms & data structuresEntry–Mid~10 min

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}.

Implement
tags_by_initial(tags: list[str]) → dict[str,int]
Examples
in[["rock","rap","pop"]]out{"p":1,"r":2}
What a strong answer looks like

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.

0:00 of about 10 min
InputExpectedGot
[["rock","rap","pop"]]{"p":1,"r":2}not run yetsample