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467 challenges 330 easy 120 medium 17 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 medium

Coin change (DP)

Find the minimum number of coins to make exactly the target amount.

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 medium

Decode Ways

Count the number of ways to decode a numeric string into letters using the mapping A=1 to Z=26.

dynamic programming strings counting

Data Structures & Algorithms medium

Redundant Connection

Given a list of edges forming a tree plus one extra edge, return the edge that appears last in the input and creates a cycle.

graphs union-find cycle-detection

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.