PHP实现的字符串匹配算法示例【sunday算法】

<?php/* *@param $pattern 模式串 *@param $text 待匹配串 */function mySunday($pattern = '',$text = ''){  if(!$pattern || !$text) return false;  $pattern_len = mb_strlen($pattern);  $text_len = mb_strlen($text);  if($pattern_len >= $text_len) return false;  $i = 0;  for($i = 0; $i < $pattern_len; $i++){ //组装以pattern中的字符为下标的数组    $shift[$pattern[$i]] = $pattern_len - $i;  }  while($i <= $text_len - $pattern_len){    $nums = 0;   //匹配上的字符个数    while($pattern[$nums] == $text[$i + $nums]){      $nums++;      if($nums == $pattern_len){        return "The first match index is $i/n";      }    }    if($i + $pattern_len < $text_len && isset($shift[$text[$i + $pattern_len]])){ //判断模式串后一位字符是否在模式串中      $i += $shift[$text[$i + $pattern_len]];   //对齐该字符    }else{      $i += $pattern_len;   //直接滑动pattern_len位    }  }}$text = "I am testing mySunday on sunday!";$pattern = "sunday";echo mySunday($pattern,$text);

The first match index is 25