[LeetCode] 3. Longest Substring Without Repeating Characters

＂踏上LeetCode解題之路，順手紀錄一下PHP練功的過程囉。這是第二篇~~＂

Longest Substring Without Repeating Characters - LeetCode

題目要求

Given a string s, find the length of the longest substring without repeating characters.

思考過程

1. 先取得字串長度strlen($s)
2. ...

❎

class Solution {

    /**
     * @param String $s
     * @return Integer
     */
    function lengthOfLongestSubstring($s) {
        
        $x= strlen($s);
        $text = "";
        $number=0;
        $list = [0];
        
        for($i=0; $i<$x; $i++){
            
            if ($s[$i] != $s[$i+1] && !str_contains($text, $s[$i]) ){
                
                $text= "$text+$s[$i]";
                $number++;
                $list[$i]= $number;
                /* $list=[1,2,3....]*/
            
                
  
            }elseif($s[$i] == $s[$i+1]){
                
                /*echo $s[$i];*/ 
                
               
                $number=0;
                
                
            }else{
                
            echo '';    
            }
        
        }

參考解答

class Solution {

    /**
     * @param String $s
     * @return Integer
     */
    function lengthOfLongestSubstring($s) {
        if(strlen($s) == 0) return 0;
        $strarr = str_split($s); 
        $substr = [];
        $max_len = 1; 
        foreach($strarr as $i) {          
          $found = array_search($i,$substr) ;
          
          if($found === false) {            
            $substr[] = $i;
            if(count($substr) > $max_len){
              $max_len = count($substr);
            }            
          } else {
            $substr[] = $i;
            $found += 1;
            $sliced_array = array_slice($substr, $found);
            $substr = $sliced_array;     
          }
        }
      return $max_len;
    }
}