Package edu.princeton.cs.algs4
Class TransitiveClosure
 Object

 edu.princeton.cs.algs4.TransitiveClosure

public class TransitiveClosure extends Object
TheTransitiveClosure
class represents a data type for computing the transitive closure of a digraph.This implementation runs depthfirst search from each vertex. The constructor takes Θ(V(V + E)) in the worst case, where V is the number of vertices and E is the number of edges. Each instance method takes Θ(1) time. It uses Θ(V^{2}) extra space (not including the digraph).
For large digraphs, you may want to consider a more sophisticated algorithm. Nuutila proposes two algorithm for the problem (based on strong components and an interval representation) that runs in Θ(E + V) time on typical digraphs. For additional documentation, see Section 4.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
 Author:
 Robert Sedgewick, Kevin Wayne


Constructor Summary
Constructors Constructor Description TransitiveClosure(Digraph G)
Computes the transitive closure of the digraphG
.

Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static void
main(String[] args)
Unit tests theTransitiveClosure
data type.boolean
reachable(int v, int w)
Is there a directed path from vertexv
to vertexw
in the digraph?



Constructor Detail

TransitiveClosure
public TransitiveClosure(Digraph G)
Computes the transitive closure of the digraphG
. Parameters:
G
 the digraph


Method Detail

reachable
public boolean reachable(int v, int w)
Is there a directed path from vertexv
to vertexw
in the digraph? Parameters:
v
 the source vertexw
 the target vertex Returns:
true
if there is a directed path fromv
tow
,false
otherwise Throws:
IllegalArgumentException
 unless0 <= v < V
IllegalArgumentException
 unless0 <= w < V

main
public static void main(String[] args)
Unit tests theTransitiveClosure
data type. Parameters:
args
 the commandline arguments

