PHP实现的最大正向匹配算法示例讲解

$dict = array(
  '本站'=>'本站',
  '脚本下载'=>'脚本下载',
  'JS编程'=>'JS编程'
);

/*
 * $query 查询词
 * $dict 词典
 * $max_len 最大长度
 */
function extractWords($query,$dict,$max_len=15){
    $feature = "";
    $slen=mb_strlen($query,'UTF8');
    $c_bg = 0;
    while($c_bg<$slen){
      $matched = false;
      $c_len =(($slen-$c_bg)>$max_len)?$max_len:($slen-$c_bg);
      $t_str = mb_substr($query, $c_bg,$c_len,'UTF8');
      for($i=$c_len;$i>1;$i--){
        $ttts = mb_substr($t_str, 0,$i,'UTF8');
          if(!empty($dict[$ttts])){
//          echo 'matched = '.$ttts.PHP_EOL;
            $matched = true;
            $c_bg += $i;
            if(!empty($feature)){
              $feature.=",";
            }
            $feature.=$ttts;
            break;
          }
      }
      if(!$matched){
        $c_bg++;
      }
    }
    echo $feature.PHP_EOL;
}

$query='欢迎访问本站！本站是国内专业的网站,提供各种脚本下载及JS、Python、php等编程资料';
extractWords($query,$dict);

本站,本站,脚本下载