Find the Length Of Longest Substring using Sliding Window Technique

FindTheLengthOfLongestSubstring.java

class FindTheLengthOfLongestSubstring {
    public int lengthOfLongestSubstring(String s) {
        
        /**
            Examples: 
          
              #1 - 
                eabcdabcbb = 4
                "abcd" is the longest substring
                4 is the length of "abcd"

              #2 -             
              bbbbb = 1
              "b" is the longest substring
              1 is the length of the substring "b" (which is just one character)

              #3 -                
              pwwkew = 3
              "pww" is the longest substring
              3 is the length of "pww"

         */

         Map<Character, Integer> map = new HashMap<Character, Integer>();
         int result = 0;

        /**
        * This For loop with two pointers (left, right) is an implementation of
        * the Sliding Window Technique
        */

        for (int left=0, right=0; right < s.length(); right++ ){

            // check map if it already contains the character
            if (map.containsKey(s.charAt(right))){
                int indexOfExistingChar = map.get(s.charAt(right));
                // Update the value of the left pointer
                // to the index of the matched character, 
                // or to its current value, whichever is greater. 
                left = Math.max(indexOfExistingChar, left);    
            }

            // Update the result value by getting the difference 
            // of the right and left pointer plus 1 (as per the requirement)
            // or to its current value, whichever is greater
            result = Math.max(right - left + 1, result);

            // Put the Character as the key and the index as the value
            map.put(s.charAt(right), right+1);

        }




        //  while (right < ch.length){ 

        //     System.out.println(ch[right]);

        //     if(map.containsKey(ch[left])){
        //         left = Math.max(map.get(ch[left]),left);
             
        //     }else{
        //         result++;
        //     }
        //     map.put(ch[right],right);
        //     right++;
            
        //  }

        return result;

    }
}