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Python Coding
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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

Python Basics easy

Clamp a Number to a Range

Implement a clamp function that returns a value within a specified range.

numbers conditionals comparisons

Python Basics easy

Count down from n

Implement a function that returns a list from n down to 1.

loops range lists

Python Basics easy

Count Multiples in a Range

Given a start, end, and divisor, count how many integers in [start, end] are divisible by the divisor.

multiples range divisibility

Python Basics easy

Range of values

Calculate the range (max minus min) of a list of numbers. Empty list returns 0.

min max numbers

Lists & Arrays easy

Move Zeros to End

Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.

list in-place two-pointer

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 easy

Rearrange Positives and Negatives

Write a function that rearranges a list in-place so all negative numbers come before non-negative numbers.

in-place two-pointers partition

Lists & Arrays easy

Wave sort array

Given a list of integers, reorder it into a wave pattern where elements alternate down-up, and return the new list.

sorting swap rearrangement

Data Structures & Algorithms medium

Bucket Sort

Implement bucket sort to sort a list of floating-point numbers in the range [0,1).

sorting bucket-sort insertion-sort

Iterators & Generators easy

Range-like generator

Implement a custom generator that yields numbers like Python's range but with flexible bounds.

generator yield range

Bit Manipulation medium

Bitwise AND of a Range

Given a range [a, b], return the bitwise AND of all integers in that inclusive range without iterating over all numbers.

bitwise range optimization

Dynamic Programming medium

House Robber Circular

Solve the House Robber problem with houses arranged in a circle.

dynamic-programming arrays circular

Trees & Binary Trees medium

Trim BST to range

Implement a function to trim a BST to only retain nodes with values in a given inclusive range.

bst recursion tree-pruning

Matrix & 2D Arrays medium

Rotting Oranges Time

Given a grid of fresh, rotten, and empty cells, compute the minimum minutes until all fresh oranges rot, or -1 if some are unreachable.

bfs grid simulation

Showing 14 challenges

Guide: free Python coding challenges

Practice Python by solving problems

PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.

How to use the arena

Pick a category — basics, algorithms, strings, and more
Open a challenge, read the statement, and edit the starter code
Run tests, fix failures, then try a related quiz or tutorial lesson

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.