Practice Arena

Python Coding Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

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
Python Basics medium

Basic Calculator

Implement a function that evaluates a simple arithmetic expression with +, -, *, / and parentheses.

calculator parsing math
+20 pts 25m
OOP & Classes medium

Complex Number Class

Implement a Complex class supporting addition, subtraction, multiplication, division, equality, and string formatting.

classes magic-methods arithmetic
+20 pts 25m
Data Structures & Algorithms medium

Basic Calculator II

Evaluate a basic arithmetic expression with +, -, *, / following operator precedence.

string stack arithmetic
+25 pts 30m
Data Structures & Algorithms medium

Arithmetic Slices Count

Given a list of integers, count how many contiguous subarrays of length at least 3 form an arithmetic sequence.

arrays arithmetic counting
+15 pts 20m
Math & Number Theory medium

Zeller Congruence Weekday

Implement a function that returns the weekday name for a given date using Zeller's congruence.

math modular-arithmetic date
+20 pts 20m
Math & Number Theory medium

Multinomial coefficient

Write a function to compute the multinomial coefficient efficiently for given nonnegative counts.

combinatorics math division
+20 pts 20m
Math & Number Theory medium

Binomial Coefficient

Implement a function to compute binomial coefficients modulo 10^9+7 for n up to 10^5.

modular-arithmetic combinatorics dynamic-programming
+25 pts 25m
Bit Manipulation medium

Divide using shifts

Implement division of two integers using only bit shifts and arithmetic, without using division or modulo operators.

integer division bit shifts overflow
+20 pts 20m
Dynamic Programming medium

Longest Arithmetic Subsequence

Given a list of integers, return the length of the longest arithmetic subsequence (constant difference) within it.

dp subsequence hashmap
+30 pts 25m
Stacks & Queues medium

Evaluate Reverse Polish Notation

Evaluate an arithmetic expression written in reverse Polish notation using a stack.

stacks arithmetic parsing
+25 pts 25m
Datetime & Time Calculations medium

Julian Day Number Converter

Implement two functions to convert between Gregorian calendar dates and Julian Day Numbers using a standard formula.

datetime date-arithmetic algorithms
+20 pts 20m

Showing 1–11 of 11 challenges · medium

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

  1. Pick a category — basics, algorithms, strings, and more
  2. Open a challenge, read the statement, and edit the starter code
  3. 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.