What is Kahn's algorithm for topological sort?

Queue-based BFS using indegrees. Processes zero-indegree nodes first, unlocks dependents. Counts completions to verify no cycles.

How to solve LeetCode Course Schedule with Kahn's?

Build adj list (prereq -> course), compute indegrees, queue zeros, BFS decrement and enqueue. Return count == numCourses.

No—Kahn's detects by unfinished nodes. Use for DAG validation only.

🛠️ Developer Tools

University prereqs got you in a loop? Kahn's algorithm slices through graph dependencies like a hot knife. No cycles, no problem.

theAIcatchup Apr 10, 2026 4 min read

Kahn's algorithm uses BFS and indegrees for efficient topological sort in O(V+E). 𝕏
Essential for detecting cycles in course dependencies or build graphs. 𝕏
Real-world use in Make, Gradle, Airflow— not just LeetCode interviews. 𝕏

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#DAG cycle detection #Kahn's algorithm #LeetCode course schedule #dependency management #graph algorithms #kahn-algorithm #topological sort

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Originally reported by Dev.to