using System;

using System.Collections.Generic;

public class Program

{

    //Implement an algorithm to determine if string has all unique characters. What if you cannot use additional data structure?

    public static void Main()

    {

        String str = "abcdefg";

        str = str.Replace(" ","");

        Console.WriteLine(str);

        bool flag = false;

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

        foreach(char c in str)

        {

            //if it in char pool does not contain unique char

            if(s.ContainsKey(c))

            {

                flag = true;

            }

            else

            {

                s.Add(c,1);

            }

        }

        if(flag)

        {

            Console.WriteLine("Duplicate char present ");

        }

        else{

            Console.WriteLine("No Duplicate");

        }

        string st = "abc";

        foreach(char c in  st)

        {

            foreach(char ch in st)

            {

                Console.WriteLine(ch ^c);

            }

        }

    }

}