A* Pathfinding Heuristic
Implement A* search on a 2D grid to find the shortest path length between two cells.
Swim in Rising Water
Find the minimum time needed to swim from the top-left to the bottom-right of a grid where water level rises and you can only move to cells with elevation ≤ current time.
Min Heap Class
Build a MinHeap class with push, pop, peek, and size methods that maintain a valid min-heap.
Kth Largest Element in an Array (Heap Edition)
Implement a function that returns the kth largest element in an unsorted integer array using a heap.
Last Stone Weight
Given an array of stone weights, repeatedly smash the two heaviest stones and return the last remaining weight or 0.
Maximum Average Pass Ratio
Given class pass/total counts and extra students, maximize the average pass ratio by assigning extra students optimally.
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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.