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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 easy

Valid parentheses

Return True if brackets in the string close in the correct order.

Data Structures & Algorithms easy

Count pairs with given difference

Count how many unordered pairs in a list have a given absolute difference using an efficient approach.

hash map counting arrays

Data Structures & Algorithms easy

Bubble Sort

Implement bubble sort that sorts a list of numbers in ascending order.

sorting arrays algorithms

Data Structures & Algorithms easy

Selection Sort Implementation

Implement selection sort to sort a list of numbers in ascending order.

sorting selection-sort algorithm

Showing 4 challenges · easy · 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.