Real-World Coding Focus | Dataford Interview Questions

Tell me about a time you adapted your coding approach because the problem was not like typical LeetCode exercises.

For the hands-on portion, implement a one-pass duplicate detector that works with an iterable rather than assuming a reusable, indexable array. Return the first value whose second occurrence is encountered, or None if every value is unique.

Function: def first_duplicate(values):

Constraints

values is an iterable of hashable values
The iterable may be a generator and may be consumed only once
Return the first value whose second occurrence is encountered
Return None when no value repeats

Function Signature

def first_duplicate(values):

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

Problem

Tell me about a time you adapted your coding approach because the problem was not like typical LeetCode exercises.

Function: def first_duplicate(values):

Constraints

values is an iterable of hashable values
The iterable may be a generator and may be consumed only once
Return the first value whose second occurrence is encountered
Return None when no value repeats

Function Signature

def first_duplicate(values):

Your question is Real-World Coding Focus. 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.