public class TransitiveClosure extends Object
TransitiveClosure
class represents a data type for
computing the transitive closure of a digraph.
This implementation runs depth-first search from each vertex. The constructor takes time proportional to V(V + E) (in the worst case) and uses space proportional to V^{2}, where V is the number of vertices and E is the number of edges.
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 E + V time on typical digraphs. For additional documentation, see Section 4.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
Constructor and Description |
---|
TransitiveClosure(Digraph G)
Computes the transitive closure of the digraph
G . |
public TransitiveClosure(Digraph G)
G
.G
- the digraphpublic boolean reachable(int v, int w)
v
to vertex w
in the digraph?v
- the source vertexw
- the target vertextrue
if there is a directed path from v
to w
,
false
otherwiseIllegalArgumentException
- unless 0 <= v < V
IllegalArgumentException
- unless 0 <= w < V
public static void main(String[] args)
TransitiveClosure
data type.args
- the command-line arguments