using System;

​

using System.Collections.Generic;

public class Program

{

    public static void Main(string[] args)

    {

        string test = "wwkewsew";//Should be 3 here

        LongestSubstringWithoutRepetition(test);

    }

    public static void LongestSubstringWithoutRepetition(string s){

        Dictionary<char,int> map = new Dictionary <char,int>();

        int maxStart = 0;

        int maxSize = 0;

        //Sliding Window pattern, start end declare the start end index of current window.

        int start = 0;

        for(int end = 0; end < s.Length; end++){

            if(map.ContainsKey(s[end])){

                start = Math.Max(start, map[s[end]]+1);

            }

            map[s[end]] = end;

            if(maxSize < end-start+1){

                maxSize = end-start+1;

                maxStart = start;

            }

        }

        Console.WriteLine("Max Substring Length Without repetition is: " + maxSize);

        Console.WriteLine("Max Substring is: " + s.Substring(maxStart, maxSize));

    }

}