缺少数组值

Question

我在php中有这个代码（基于BFS的算法）.. JARAK表示DISTANCE（节点级别）。

$vsourceuser = 'A';

if(!empty($vsourceuser)) {     
    $queue = array();
    $visited_node = array();
    $jarak = array();

    $queue[0] = $vsourceuser;
    $index_vn = 0;
    $visited_node[0] = $vsourceuser;
    $jarak[0] = 0;
    $level = 0;
    $max_jarak = 0;
    $arrneighbor[] = array();

    while(!empty($queue)) {
        $level=$level+1;
        $m = count($queue);
        $j=0;
        if($j<$m) {
            $fnode=reset($queue);
            //$fnode = current($queue);
            $rsrow = mysql_query("select * from matrik_trust WHERE row='$fnode' AND connect=1") or die(mysql_error());
            $n = mysql_num_rows($rsrow);
            if($n>0) { //is there neighbor?
                while($row = mysql_fetch_array($rsrow)) {
                        $arrneighbor[] = $row;
                }
                array_shift($arrneighbor);
                reset($arrneighbor);
                for($i=0;$i<$n;$i++) { //15
                    $neighbor = $arrneighbor[$i]['column'];

                    array_push($queue,$neighbor); //16
                    if(in_array(end($queue),$visited_node)) { //17 18
                        array_pop($queue); //19 
                    } else { //20
                        $index_vn = $index_vn+1;
                        $visited_node[$index_vn]=end($queue);
                        $jarak[$index_vn]=$level; 
                    }
                }
                array_shift($queue); //24
            } else { //theres no neighbor 25
                array_shift($queue); // 26
            }
            $j=$j+1;
        }           
    }

    if(empty($queue)) {
        $max_jarak = $level-1;
        if($max_jarak==0) {
                echo "Theres no neighbor to this node.";
        } else {
                echo '<br>max jarak :'.$max_jarak.'<br><br>';
                echo '<br>visited node :<br>'.print_r($visited_node);
                echo '<br>distance :'.print_r($jarak);
        }
    }
} else {
echo "Must fill the source."; 
} ?>

下面有数据访问..

----------------------------
id | row | column | connect|
----------------------------
AA |  A  |   A    |    0   |
AB |  A  |   B    |    1   |
AC |  A  |   C    |    1   |
AD |  A  |   D    |    0   |
BA |  B  |   A    |    1   |
BB |  B  |   B    |    0   |
BC |  B  |   C    |    0   |
BD |  B  |   D    |    1   |
..   ..     ..        ..
(C and D not related to anyone or all connect value to row C and D is 0)

我希望，这可以输出..

*************[ I WISH ]**************
maxsimum distance = 2
-------------------------------------------
index|    $visited_node | $jarak (distance)
-------------------------------------------
 0   |    A             | 0
 1   |    B             | 1 
 2   |    C             | 1  
 3   |    D             | 2

我已经跟踪了那个算法，我脑子里的输出就是上面那个。但实际上，结果总是如此：

********[ REALITY ]********
maxsimum distance = 2
visited node: Array ( 
                  [0] => A 
                  [1] => B 
                  [2] => C 
             )
distance:     Array ( 
                  [0] => 0 
                  [1] => 1 
                  [2] => 1 
             )

你能看到...... D缺失了它的距离。当我追踪我的语法时，D总是存在，但输出总是那样。我不知道为什么......语法有什么问题？ 有人能帮助我吗？