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Python Coding
Challenges

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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

Lists & Arrays medium

Product of All Except Zeros Handling

Given a list of integers, return a list where each element is the product of all other elements, handling zeros correctly.

product arrays zero-handling

Lists & Arrays medium

Find Duplicate Number

Given a list of n+1 integers in the range 1..n, find the one integer that appears more than once.

arrays hash-set duplicates

Lists & Arrays medium

Two Missing Numbers

Given a list of n-2 unique integers from 1 to n, find the two missing numbers efficiently.

missing-numbers arrays math

Lists & Arrays medium

Three Missing Numbers

Find the three missing numbers from a shuffled list containing all but three integers from 1 to n.

arrays sets missing

Showing 4 challenges · medium · Lists & Arrays

Lists & Arrays — Python coding challenges

What you will find here

This page lists lists & arrays 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.