Practice Arena

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
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
+30 pts 30m
Data Structures & Algorithms medium

Heap Sort Implementation

Implement the heap sort algorithm to sort a list of comparable elements in non-decreasing order.

heap sorting in-place
+20 pts 25m
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
+25 pts 30m
Dynamic Programming medium

Levenshtein Distance

Implement the classic Levenshtein distance algorithm to measure string similarity.

strings dynamic-programming edit-distance
+30 pts 30m
Dynamic Programming medium

Edit Distance (Levenshtein Distance)

Implement the classic edit distance algorithm to find the minimum number of single-character edits required to transform one string into another.

dynamic-programming strings levenshtein-distance
+25 pts 30m
Dynamic Programming medium

Coin Change Minimum

Given coin denominations and a target amount, compute the minimum number of coins needed or -1 if impossible.

dynamic-programming coins minimum
+30 pts 25m
Graphs & Graph Algorithms medium

Bellman-Ford Algorithm

Implement the Bellman-Ford algorithm to compute shortest distances from a source in a directed weighted graph with up to 100 vertices and negative edges.

shortest-path negative-edges graph
+30 pts 30m
Two Pointers & Sliding Window medium

Sort Colors (Dutch National Flag)

Implement the Dutch National Flag algorithm to sort an array of 0, 1, 2 in one pass.

in-place two-pointers sorting
+20 pts 25m

Showing 8 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.