PHP 最长公共子序列LCS 中文汉字版本怎么写？

<code><?php //最长公共子序列英文版
function LCS_en($str_1, $str_2) {
  $len_1 = strlen($str_1);
  $len_2 = strlen($str_2);
  $len = $len_1 > $len_2 ? $len_1 : $len_2;

  $dp = array();
  for ($i = 0; $i  $dp[$i][$j - 1] ? $dp[$i - 1][$j] : $dp[$i][$j - 1];
      }
    }
  }

  return $dp[$len_1][$len_2];
}

//拆分字符串
function mbStringToArray($string, $encoding = 'UTF-8') {
  $arrayResult = array();

  while ($iLen = mb_strlen($string, $encoding)) {
    array_push($arrayResult, mb_substr($string, 0, 1, $encoding));
    $string = mb_substr($string, 1, $iLen, $encoding);
  }

  return $arrayResult;
}

//最长公共子序列中文版
function LCS_cn($str1, $str2, $encoding = 'UTF-8') {
  $mb_len1 = mb_strlen($str1, $encoding);
  $mb_len2 = mb_strlen($str2, $encoding);

  $mb_str1 = mbStringToArray($str1, $encoding);
  $mb_str2 = mbStringToArray($str2, $encoding);

  $len = $mb_len1 > $mb_len2 ? $mb_len1 : $mb_len2;

  $dp = array();
  for ($i = 0; $i  $dp[$i][$j - 1] ? $dp[$i - 1][$j] : $dp[$i][$j - 1];
      }
    }
  }

  return $dp[$mb_len1][$mb_len2];
}
</code>