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Python Coding
Challenges

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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 medium

Quicksort

Implement quicksort and return a sorted list.

sorting recursion divide-and-conquer

Data Structures & Algorithms medium

Graph DFS

Return all nodes reachable from a start node via DFS.

graph DFS recursion

Data Structures & Algorithms easy

Employee Hierarchy

Build an employee hierarchy tree and compute the total number of direct and indirect reports for each employee.

Data Structures & Algorithms medium

Merge Sort

Implement merge_sort(numbers) that returns a sorted copy of the input list using the merge sort algorithm.

sorting recursion divide-and-conquer

Data Structures & Algorithms easy

Lowest Common Ancestor in a Binary Search Tree

Implement a function to find the lowest common ancestor of two node values in a binary search tree.

Data Structures & Algorithms hard

N-Queens Solutions

Implement a function to count the number of distinct ways to place n queens on an n×n board.

backtracking chess recursion

Data Structures & Algorithms medium

Strobogrammatic number II

Given a positive integer n, return all strobogrammatic numbers of length n in ascending order.

strings recursion number

Showing 1–7 of 7 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.