You are given n courses numbered from 0 to n-1 and a prerequisite array of pairs where each element is a pair [a,b], which represents that to complete course a, course b needs to be finished first. Can you finish all the courses?

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Accepted Answer

The optimized solution was to make an adjacency list of all the prerequisites of all the courses and do a dfs to check if we can complete the courses. If there is a cycle then we cannot complete the courses. It was basically checking cycles in a Directed graph.