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925 challenges 556 easy 323 medium 46 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 hard

Longest increasing subsequence

Return the length of the longest strictly increasing subsequence.

dp binary-search LIS

Data Structures & Algorithms hard

Median of Two Sorted Arrays

Given two sorted arrays, return the median of the combined sorted array in O(log(min(n,m))) time.

median binary search arrays

Data Structures & Algorithms hard

Knight Tour Count

Implement a backtracking search to count all ways a knight can visit every cell on a 5x5 board exactly once starting from (0,0).

backtracking dfs board

Showing 1–3 of 3 challenges · hard · 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.