<?php

function shortPath($from, $to)
{
    $queue = array($from);
    $active = 0;
    $prev = array();
    
    while ( count($queue) > 0 )
    {
        $active = array_shift($queue); 
        $dbresult = mysql_query("SELECT `ven` FROM `vennetabel` WHERE `bruger` = $active"); 
        while ($enven = mysql_fetch_assoc($dbresult))
        {
            $enven = $enven['ven'];
            if (!empty($prev[$enven]))
                continue; 
            $prev[$enven] = $active;
            array_push($queue,$enven);
            
            if ($enven == $to)
                return backTrack($from, $to, $prev); 
        }
    }
    return "No path exists between $from and $to";
}

function backTrack($from, $to, $prev)
{
    $output = array($to);
    $active = $to;
    while ($active != $from)
    {
        $active = $prev[$to];
        array_unshift($output,$active);
    }
    return $output;
}

?>