Remove duplicates (sorted)
Return a sorted list with duplicates removed.
Merge two sorted arrays
Merge two sorted arrays into one sorted array.
Merge intervals
Merge all overlapping intervals and return a sorted result.
Second Largest Unique Value
Return the second largest distinct integer from a list, or None if it doesn't exist.
Insert into a Sorted List
Implement a function that inserts a value into a sorted list at the correct position using binary search.
Average excluding min and max
Return the average of a list after discarding the lowest and highest elements, handling edge cases.
Find Second Largest
Find the second largest unique number in a list, or None if it doesn't exist.
Move Zeros to End
Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.
Intersection of Two Lists
Given two lists, return a sorted list of unique elements that appear in both lists.
Wave sort array
Given a list of integers, reorder it into a wave pattern where elements alternate down-up, and return the new list.
Counting Sort
Implement the counting sort algorithm to sort a list of non-negative integers in O(n + k) time.
Showing 11 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.