scala mapreduce project

Given a directed graph and a number k, compute the number of cycles with length k. A cycle is a path with the same source and target node, and it does not contain smaller cycles. For example, in the below graph, 0->1->3->4->0 is a cycle with length 4, but 2->3->4->3->2 is not a cycle with length 4, since 2->3->2 and 3->4->3 are also cycles in the path. See in first graph1 Input: Each line is in format of “EdgeId FromNodeId ToNodeId”. Given the left graph, the input file is like below. see in second graph2 Output: Show the number of cycles with length k. For example, given the sample tiny graph and 4, the result is 3: 0->1->3->4->0, 0->1->2->4->0, and 0->2- >3->4->0. Note that 0->1->3->4->0 and 1->3->4->0->1 are the same cycle, and they only contribute 1 to the count.