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819 challenges 506 easy 280 medium 33 hard

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Lists & Arrays easy

Remove duplicates (sorted)

Return a sorted list with duplicates removed.

arrays two-pointer

Lists & Arrays easy

Merge two sorted arrays

Merge two sorted arrays into one sorted array.

arrays merge two-pointer

Lists & Arrays easy

Move Zeros to the End

Reorder a list in-place, pushing all zeros to the end while preserving the order of non-zero numbers.

lists in-place two-pointer

Lists & Arrays medium

Partition around a pivot value

Implement an in-place partition of a list around a given pivot value, returning the boundary index.

lists partition two-pointer

Lists & Arrays easy

Move Zeros to End

Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.

list in-place two-pointer

Lists & Arrays easy

Rearrange Positives and Negatives

Write a function that rearranges a list in-place so all negative numbers come before non-negative numbers.

in-place two-pointers partition

Lists & Arrays easy

Move Zeroes

Implement move_zeroes(nums) that in-place moves all zeros to the end while maintaining the order of non-zero elements.

arrays in-place two-pointers

Lists & Arrays easy

Sort array by parity

Given a list of integers, return a new list with all evens first and odds last, preserving original relative order.

sorting arrays two-pointers

Lists & Arrays easy

Merge Sorted Array In Place

Write a function that merges two sorted arrays into the first array in-place, keeping the result sorted.

arrays sorting in-place

Showing 9 challenges · Lists & Arrays

Lists & Arrays — Python coding challenges

What you will find here

This page lists lists & arrays challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.

Challenges vs tutorials and quizzes

Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.