Find Duplicates in a String | Dataford Interview Questions

Write a program to find duplicates in the string.

Asked in the One-on-one Round - 1 stage. It was the opening coding task of the first one-on-one round, alongside basic C and C++ questions.

Implement find_duplicates(s). Treat letters case-insensitively, preserve the first character spelling, and return each qualifying character once in order of first appearance. A letter qualifies when its lowercase form occurs more than once or it is a vowel. Whitespace characters also qualify when present. Ignore other single-occurrence characters.

Input and Output

s is a string. Return a list of strings, where each element is one character.

Constraints

0 <= len(s) <= 10^5
The string may contain Unicode letters, whitespace, and punctuation
Each output element is a single-character string
Output order follows first occurrence in the input

Function Signature

def find_duplicates(s):

Your question is Find Duplicates in a String. 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