trie 的应用
应 CSDN 要求，收到 CSDN 月饼的应发散分贴
前贴已发，由于僧多粥少。故此结贴，比继续发帖散分
class TTrie {<br />
protected $buffer = array();<br />
protected $dict = array( array() );<br />
protected $input = 0; //字符串当前偏移<br />
protected $backtracking = 0; //字符串回溯位置<br />
public $debug = 0;<br />
public $savematch = 1;<br />
<br />
function set($word, $action='') {<br />
if(is_array($word)) {<br />
foreach($word as $k=>$v) $this->set($k, $v);<br />
return;<br />
}<br />
$p = count($this->dict);<br />
$cur = 0; //当前节点号<br />
foreach(str_split($word) as $c) {<br />
if (isset($this->dict[$cur][$c])) { //已存在就下移<br />
$cur = $this->dict[$cur][$c];<br />
continue;<br />
}<br />
$this->dict[$p]= array(); //创建新节点<br />
$this->dict[$cur][$c] = $p; //在父节点记录子节点号<br />
$cur = $p; //把当前节点设为新插入的<br />
$p++;<br />
}<br />
$this->dict[$cur]['acc'] = $action; //一个词结束，标记叶子节点<br />
}<br />
<br />
function match($s) {<br />
$ret = array();<br />
$cur = 0; //当前节点，初始为根节点<br />
$i =& $this->input; //字符串当前偏移<br />
$p =& $this->backtracking; //字符串回溯位置<br />
$s .= "\0"; //附加结束符<br />
$len = strlen($s);<br />
$buf = '';<br />
while($i < $len) {<br />
$c = $s{$i};<br />
if(isset($this->dict[$cur][$c])) { //如果存在<br />
$cur = $this->dict[$cur][$c]; //转到对应的位置<br />
if(isset($this->dict[$cur][$s[$i+1]])) {//检查下一个字符是否也能匹配，长度优先<br />
$i++;<br />
continue;<br />
}<br />
if(isset($this->dict[$cur]['acc'])) { //是叶子节点，单词匹配！<br />
if($buf != '') {<br />
$this->buffer[] = $buf;<br />
$buf = '';<br />
}<br />
if($this->savematch) $this->buffer[] = substr($s, $p, $i - $p + 1); //取出匹配位置和匹配的词<br />
<br />
$ar = explode(',', $this->dict[$cur]['acc']);<br />
call_user_func_array( array($this, array_shift($ar)), $ar );<br />
<br />
$p = $i + 1; //设置下一个回溯位置<br />
$cur = 0; //重置当前节点为根节点<br />
}<br />
} else { //不匹配<br />
$buf .= $s{$p}; //substr($s, $p, $i - $p + 1); //保存未匹配位置和未匹配的内容<br />
$cur = 0; //重置当前节点为根节点<br />
$i = $p; //把当前偏移设为回溯位置<br />
$p = $i + 1; //设置下一个回溯位置<br />
}<br />
$i++; //下一个字符<br />
}<br />
if(trim($buf, "\0")) $this->buffer[] = trim($buf, "\0");<br />
}<br />
<br />
function __call($method, $param) {<br />
if($this->debug) printf("偏移:%d 回溯:%d\n", $this->input, $this->backtracking);<br />
<br />
}<br />
}<br />
