Practice Arena

Python Coding Challenges

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

577 challenges 370 easy 180 medium 27 hard
Data Structures & Algorithms easy

Previous Smaller Element

Find the nearest previous index with a smaller value for every element in an array.

arrays stack monotonic-stack
+10 pts 15m
Data Structures & Algorithms medium

Next greater element II

For each element in a circular array, find the next greater element (NGE) to its right, wrapping around.

arrays stack monotonic stack
+20 pts 20m
Data Structures & Algorithms medium

Online Stock Span

Implement StockSpanner.next(price) that returns the maximum number of consecutive days (including today) with price <= current price.

stack monotonic-stack stock-span
+20 pts 25m
Stacks & Queues easy

Next Greater Element

Return a list where each position holds the next greater element to the right, or -1 if none exists.

stack arrays monotonic stack
+10 pts 15m
Stacks & Queues medium

Daily Temperatures

Given a list of daily temperatures, return for each day how many days until a warmer temperature appears.

stacks arrays monotonic-stack
+25 pts 25m
Stacks & Queues medium

Remove K Digits Stack

Remove k digits from a non-negative integer string to produce the smallest possible number using a stack-based approach.

stack string greedy
+25 pts 25m
Stacks & Queues medium

Buildings with ocean view

Given building heights, return sorted indices of buildings that have a clear view of the ocean to their right.

stack monotonic-stack arrays
+20 pts 20m
Stacks & Queues medium

Sum of Subarray Minimums

Given an integer array, sum the minimum of all contiguous subarrays modulo 10^9+7.

stack array monotonic-stack
+30 pts 30m

Showing 8 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

  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.