DepthFirstDirectedPaths (Algorithms 4/e)

Object
- edu.princeton.cs.algs4.DepthFirstDirectedPaths

```
public class DepthFirstDirectedPaths
extends Object
```
The DepthFirstDirectedPaths class represents a data type for finding directed paths from a source vertex s to every other vertex in the digraph.
This implementation uses depth-first search. The constructor takes Θ(V + E) time 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) extra space (not including the digraph).
See DepthFirstDirectedPaths for a nonrecursive implementation. 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

DepthFirstDirectedPaths(Digraph G, int s)
Computes a directed path from s to every other vertex in digraph G.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`hasPathTo(int v)`	Is there a directed path from the source vertex `s` to vertex `v`?
`static void`	`main(String[] args)`	Unit tests the `DepthFirstDirectedPaths` data type.
`Iterable<Integer>`	`pathTo(int v)`	Returns a directed path from the source vertex `s` to vertex `v`, or `null` if no such path.

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DepthFirstDirectedPaths
```
public DepthFirstDirectedPaths(Digraph G,
                               int s)
```
    Computes a directed path from s to every other vertex in digraph G.
    
    Parameters:
    
    G - the digraph
    
    s - the source vertex
    
    Throws:
    
    IllegalArgumentException - unless 0 <= s < V
- Method Detail
  - hasPathTo
```
public boolean hasPathTo(int v)
```
    Is there a directed path from the source vertex s to vertex v?
    
    Parameters:
    
    v - the vertex
    
    Returns:
    
    true if there is a directed path from the source vertex s to vertex v, false otherwise
    
    Throws:
    
    IllegalArgumentException - unless 0 <= v < V
  - pathTo
```
public Iterable<Integer> pathTo(int v)
```
    Returns a directed path from the source vertex s to vertex v, or null if no such path.
    
    Parameters:
    
    v - the vertex
    
    Returns:
    
    the sequence of vertices on a directed path from the source vertex s to vertex v, as an Iterable
    
    Throws:
    
    IllegalArgumentException - unless 0 <= v < V
  - main
```
public static void main(String[] args)
```
    Unit tests the DepthFirstDirectedPaths data type.
    
    Parameters:
    
    args - the command-line arguments