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Digraph.java in is

http://algs4.cs.princeton.edu/code/edu/princeton/cs/algs4/Digraph.java.html

4.2.7 The indegree of a vertex in a digraph is the number of directed edges that point to that vertex. The outdegree of a vertex in a digraph is the number of directed edges that emanate from that vertex. No vertex is reachable from a vertex of outdegree 0, which is called a sink; a vertex of indegree 0, which is called a source, is not reachable from any other vertex. A digraph where self-loops are allowed and every vertex has outdegree 1 is called a map (a function from the set of integers from 0 to -1 onto itself). Write a program Degrees java that implements the following API: public class Degrees Degrees (Digraph G) constructor indegree of v int indegree (int v) int outdegree (int v) out degree of v Iterable. Integer> sources sources Iterable Intege sinks sinks boolean isMapC) is G a map