Argsort Indices
Implement a function that returns the indices that would sort a list of integers, with ties broken by original order.
Level Order Traversal
Implement a function that performs a level order traversal of a binary tree and returns node values as a list of lists.
Delete duplicates sorted II
Given a sorted list, remove duplicates in place so each element appears at most twice, returning the new length.
Accounts Merge
Given a list of accounts, merge those that share any email and return sorted accounts.
Strobogrammatic number II
Given a positive integer n, return all strobogrammatic numbers of length n in ascending order.
Showing 25–29 of 29 challenges · Data Structures & Algorithms
Data Structures & Algorithms — Python coding challenges
What you will find here
This page lists data structures & algorithms 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.