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/* vim: set expandtab tabstop=4 shiftwidth=4 : */
public class SAP
{
// data type use space proportional to E + V
// all methods take time at most proportional to E + V in the worst case
// constructor takes a digraph (not necessarily a DAG)
public SAP(Digraph G)
{
}
// length of shortest ancestral path between v and w
// -1 if no such path
public int length(int v, int w)
{
// throws java.lang.IndexOutOfBoundsException if args not in [0 ; G.V()-1]
return -1;
}
// a common ancestor of v and w that participates in a shortest ancestral path
// -1 if no such path
public int ancestor(int v, int w)
{
// throws java.lang.IndexOutOfBoundsException if args not in [0 ; G.V()-1]
return -1;
}
// length of shortest ancestral path between any vertex in v and any vertex in w
// -1 if no such path
public int length(Iterable<Integer> v, Iterable<Integer> w)
{
// throws java.lang.IndexOutOfBoundsException if args not in [0 ; G.V()-1]
return -1;
}
// a common ancestor that participates in shortest ancestral path
// -1 if no such path
public int ancestor(Iterable<Integer> v, Iterable<Integer> w)
{
// throws java.lang.IndexOutOfBoundsException if args not in [0 ; G.V()-1]
return -1;
}
// for unit testing of this class (such as the one below)
public static void main(String[] args)
{
In in = new In(args[0]);
Digraph G = new Digraph(in);
SAP sap = new SAP(G);
while (!StdIn.isEmpty()) {
int v = StdIn.readInt();
int w = StdIn.readInt();
int length = sap.length(v, w);
int ancestor = sap.ancestor(v, w);
StdOut.printf("length = %d, ancestor = %d\n", length, ancestor);
}
}
}
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