DepthFirstSearch (Algorithms 4/e)

Object
- edu.princeton.cs.algs4.DepthFirstSearch

```
public class DepthFirstSearch
extends Object
```
The DepthFirstSearch class represents a data type for determining the vertices connected to a given source vertex s in an undirected graph. For versions that find the paths, see DepthFirstPaths and BreadthFirstPaths.
This implementation uses depth-first search. See NonrecursiveDFS for a non-recursive version. 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 graph).
For additional documentation, see Section 4.1 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Constructor Summary

Constructors
Constructor Description

DepthFirstSearch(Graph G, int s)
Computes the vertices in graph G that are connected to the source vertex s.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`count()`	Returns the number of vertices connected to the source vertex `s`.
`static void`	`main(String[] args)`	Unit tests the `DepthFirstSearch` data type.
`boolean`	`marked(int v)`	Is there a path between the source vertex `s` and vertex `v`?

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

- Constructor Detail
  - DepthFirstSearch
```
public DepthFirstSearch(Graph G,
                        int s)
```
    Computes the vertices in graph G that are connected to the source vertex s.
    
    Parameters:
    
    G - the graph
    
    s - the source vertex
    
    Throws:
    
    IllegalArgumentException - unless 0 <= s < V
- Method Detail
  - marked
```
public boolean marked(int v)
```
    Is there a path between the source vertex s and vertex v?
    
    Parameters:
    
    v - the vertex
    
    Returns:
    
    true if there is a path, false otherwise
    
    Throws:
    
    IllegalArgumentException - unless 0 <= v < V
  - count
```
public int count()
```
    Returns the number of vertices connected to the source vertex s.
    
    Returns:
    
    the number of vertices connected to the source vertex s
  - main
```
public static void main(String[] args)
```
    Unit tests the DepthFirstSearch data type.
    
    Parameters:
    
    args - the command-line arguments