Letter Frequency Counter | Dataford Interview Questions

How would you implement a program to determine the frequency of each letter in a given string, such as "asrfrfgg," producing an output like "a1s1r2f2g2," while considering the time and space complexity of your solution?

Asked in the Round 4: Technical - Bar Raiser stage.

Implement letter_frequency(s), accepting a string and returning one concatenated string. Each distinct character must appear once, ordered by its first appearance, followed immediately by its frequency. Treat characters exactly as provided. Return an empty string for empty input.

Constraints

0 <= len(s) <= 10^5
The input contains letters only
Characters are treated exactly as provided

Function Signature

def letter_frequency(s):

Your question is Letter Frequency Counter. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Asked in the Round 4: Technical - Bar Raiser stage.

Constraints

0 <= len(s) <= 10^5
The input contains letters only
Characters are treated exactly as provided

Function Signature

def letter_frequency(s):

Your question is Letter Frequency Counter. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.