1.1

1.1

public class isunique
{
    public static void main(String[] args)
    {
        String s = "abcderfg";
        boolean result = isunique(s);
        System.out.println(result); 
    }
    
    public static boolean isunique(String s)
    {
        if(s.length() == 0 || s.equals(null))
            return true;
            
        if(s.length() > 256)
            return false;
        
        int temp = 0;
        boolean[] flag = new boolean[256];
        for(int i = 0; i < s.length(); i++)
        {
            temp = s.charAt(i);
            if(flag[temp] == true)
                return false;
            else
                flag[temp] = true;
        }
        
        return true;
    }
}