package hashmap;

import java.util.HashMap;

import java.util.Map;

public class hashmap {

 public static void main(String[] args) {

  String s="dvdf";

        if(s==null||s.length()==0){

            System.out.println("null");

        }

        int result=1;

        Map<Character,Integer> charIndexMap= new HashMap<>();

        int[] length = new int[s.length()];

        int lastDuplicate = 0;

        length[0]=1;

        charIndexMap.put(s.charAt(0),0);

        for(int i=1;i<s.length();i++){

            Character ch = s.charAt(i);

            if(charIndexMap.containsKey(ch)){

                length[i]=i-Math.max(charIndexMap.get(s.charAt(i)),lastDuplicate);

                lastDuplicate = Math.max(lastDuplicate, charIndexMap.get(s.charAt(i)));

            }

            else{

                length[i]=length[i-1]+1;

            }

            charIndexMap.put(ch,i);

            result = Math.max(result,length[i]);

        }

       System.out.println(result);

 }

}