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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

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

Data Structures & Algorithms medium

BFS level-order traversal

Return the level-order traversal of a binary tree as a list of lists.

BFS trees queues

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

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