Course Schedule

Determine if it is possible to finish all courses given prerequisites.

10 min read

Problem Understanding

There are numCourses courses labeled 0 to numCourses - 1. You are given prerequisites array where [a, b] means taking course b is mandatory before a.

Return true if you can finish all courses, false otherwise (i.e., if there is a cycle).

Strategy (Kahn's Algorithm)

This is a Cycle Detection problem in a Directed Graph.

Build Adjacency List and In-Degree array.
Push all nodes with in-degree == 0 to Queue.
Process Queue, decrementing neighbor in-degrees.
Count how many nodes we processed.
If processed_count == numCourses, return true.

Interactive Visualization

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Custom Input

Watch how Kahn's Algorithm processes nodes with 0 in-degree. Nodes turn green when processed.

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