[LeetCode] Longest Substring without repeat characters

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. For "bbbbb" the longest substring is "b", with the length of 1.

Java Code

public int lengthOfLongestSubstring(String s) {
         int startIndex = 0;
           boolean[] visited = new boolean[256];
           int maxLen = 0;
           
           for(int i = 0; startIndex <= i && i < s.length(); i++){
               char a = s.charAt(i);
               if(!visited[a]) {
                   visited[a] = true;
               }else{
                   maxLen = maxLen > (i+1-startIndex)? maxLen : i + 1 - startIndex;
                   while(s.charAt(startIndex) != a ) {
                        visited[s.charAt(startIndex)] = false;
                       startIndex++;
                   }
                   
                   startIndex++;
               }
                   
           }
           
           maxLen = maxLen > s.length() - startIndex? maxLen : s.length() - startIndex;
           
           return maxLen;
    }