php怎么实现二叉树的存储

class node{<br />   public var $per;<br />   public var $lNode;<br />   public var $rNode;<br /><br />   function test1(){<br />   }<br /><br />   function test2(){<br />   }<br />}

$node0=new node();<br />$node0->per = 49;<br />$node1=new node();<br />$node1->per = 20;<br />$node2=new node();<br />$node2->per = 29;<br />$node0->lNode = $node1;<br />$node0->rNode = $node2;

<xmp><br /><?php<br />$s = '4 6 8 9 10 12';<br />foreach(explode(' ', $s) as $k=>$v) { //初始化<br />  $t[] = array('w' => $v, 'v' => $v); //用值作为权重<br />}<br />HuffmanTree($t);<br />echo DLR($t), PHP_EOL;<br /><br />/* 哈夫曼算法 */<br />function HuffmanTree(&$F) {<br />  while(count($F) > 1) {<br />    $r = array();<br />    foreach($F as $item) $r[] = $item['w'];<br />    array_multisort($r, $F);<br />    $t = array('w' => $F[0]['w']+$F[1]['w'], 'l' => $F[0], 'r' => $F[1]);<br />    unset($F[0]);<br />    unset($F[1]);<br />    $F[] = $t;<br />  }<br />  $F = current($F);<br />}<br />/* 前序遍历 */<br />function DLR($F, $deep=0) {<br />  echo str_repeat("   ", $deep) .'+- ' . $F['w'] . PHP_EOL;//打印权重<br />  if(isset($F['l'])) DLR($F['l'], $deep+1);<br />  if(isset($F['r'])) DLR($F['r'], $deep+1);<br />}<br />