Maintenance

Site is under maintenance — quizzes are still available.

Sponsored Reserved space — layout preview until AdSense is connected

Practice Arena

Python Coding
Challenges

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

56 challenges 25 easy 23 medium 8 hard

All Easy Medium Hard

Sponsored Reserved space — layout preview until AdSense is connected

All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python

Data Structures & Algorithms hard

LRU cache decorator

Implement @lru_cache(maxsize=N) for unary functions using OrderedDict.

decorators caching OrderedDict

Data Structures & Algorithms hard

Longest increasing subsequence

Return the length of the longest strictly increasing subsequence.

dp binary-search LIS

Data Structures & Algorithms hard

Topological sort (Kahn)

Return a valid topological ordering of tasks, or [] if a cycle exists.

graph BFS topological-sort

Data Structures & Algorithms hard

Word ladder length

Return the length of the shortest transformation from beginWord to endWord changing one letter at a time.

BFS graph strings

Showing 4 challenges · hard · filtered by category