func canFinish(_ numCourses: Int, _ prerequisites: [[Int]]) -> Bool {
    guard (prerequisites.count > 0) else {return true}
    var graph : [[Int]] = Array(repeating: [], count: numCourses + 1 )
    var inDegree : [Int] = Array(repeating: 0, count: numCourses + 1 )
    for x in prerequisites {
        graph[x[0]] += [x[1]]
        inDegree[x[0]] += 1
    }

    for course in graph.enumerated() {
        print ("To finish course \(course.offset) you must have finished \(course.element)")
    }

    for course in (inDegree.enumerated()) {
        print ("Course \(course.offset) needs \(course.element) courses to be complete")
    }

    var outputArr = [Int]()

    while let currentVertexIndx = (inDegree.enumerated().first { $0.element == 0 }?.offset) {
        outputArr.append( currentVertexIndx )
        for course in graph.enumerated() {
            if (course.element.contains(currentVertexIndx)) {
                inDegree[ course.offset ] -= 1
            }
        }
        inDegree[currentVertexIndx] = -1
    }
    return outputArr.count - 1 == numCourses
}