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Quiz

#207 Course Schedule

APPROACH

You need to pass numCourses courses labeled 0 through numCourses - 1. The array prerequisites[i] = [ai, bi] means course bi must be completed before ai.

- For instance, [0, 1] means course 1 must come first.

Return true if completing all courses is achievable, or false if a dependency cycle makes it impossible.

Example 1:

Input: numCourses = 2, prerequisites = [[1,0]]

Output: true

Explanation: There are a total of 2 courses to take.

To take course 1 you should have finished course 0. So it is possible.

Example 2:

Input: numCourses = 2, prerequisites = [[1,0],[0,1]]

Output: false

Explanation: There are a total of 2 courses to take.

To take course 1 you should have finished course 0, and to take course 0 you should also have finished course 1. So it is impossible.

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What is the optimal approach for this problem?