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875 challenges 536 easy 303 medium 36 hard

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All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

Data Structures & Algorithms easy

Delete Old Records

Filter a list of records by removing those with a date older than a given cutoff date.

filtering datetime lists

Data Structures & Algorithms medium

Delete Middle Node

Implement a function that deletes a given non-tail node from a singly linked list in O(1) time.

linked-list pointer in-place

Data Structures & Algorithms medium

Design Skip List Lite

Implement a simplified skip list supporting insert, search, and delete with O(log n) average complexity.

skip-list linked-list search

Data Structures & Algorithms medium

Delete duplicates sorted II

Given a sorted list, remove duplicates in place so each element appears at most twice, returning the new length.

arrays two-pointers in-place

Showing 4 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.