Detailed PHP implementation of depth-first search algorithm

This article mainly introduced the PHP implementation of the depth-first search algorithm (dfs,depth, first search), simple analysis of the depth-priority search algorithm principle and combined with specific examples of the implementation of PHP depth-first search for the specific steps and related operating skills, the need for friends can refer to the next

In this paper, the implementation of depth-first search algorithm in PHP is described. Share to everyone for your reference, as follows:

The implementation principle of depth-first search:

Implementation code:

<?phpclass search_method{  //non-graph array description  private $dfs _save;  Global record array  private $arr;  Control Branch-  private $k = 0;  Public function __construct ()  {    $this->dfs_save = Array (Array (      0,1,1,1,0,0,0,0,0),      Array ( 1,0,0,0,1,0,0,0,0),      Array (1,0,0,0,0,1,0,0,0),      Array (1,0,0,0,0,0,1,0,0),      Array (0,1,0,0,0,1,0,0,1 ),      Array (0,0,1,0,1,0,0,1,0),      Array (0,0,0,1,0,0,0,0,0),      Array (0,0,0,0,0,1,0,0,0),      Array ( 0,0,0,0,1,0,0,0,0),    );    $this->arr = Array ();  }  Recursive implementation of depth-first search public  function dfs ($v)  {    //Do some operations on vertices    echo str_repeat ("-", $this->k);    Echo ' V '. ($v + 1). ' <br> ';    Record the visited vertex    $this->arr[]= $v;    Find vertices connected to vertices, continue depth first search for    ($i =0; $i <9; $i + +)    {if      (!in_array ($i, $this->arr) &&$ if present this->dfs_save[$v] [$i]==1)      {        $this->k++;        $this->dfs ($i);      }    }    $this->k--;    return;}  }? >

To achieve the output result:

V1-V2--V5---V6----V3----V8---v9-v4--v7