Find first repeated character Java

PROGRAM TO FIND FIRST REPEATED CHARACTER IN A STRING IN ONE TRAVERSAL

public class First_Repeated_char {

  

    static int FirstRepeated(String str)

    {

        // An integer to store presence/absence

        // of 26 characters using its 32 bits.

        int checker = 0;

       

        for (int i = 0; i < str.length(); ++i)

        {

            int val = (str.charAt(i)-'a');

       

            // If bit corresponding to current

            // character is already set

            if ((checker & (1 << val)) > 0)

                return i;

       

            // set bit in checker

            checker |= (1 << val);

        }

       

        return -1;

    }

       

    // Driver code

    public static void main(String args[])

    {

        String s = "abcfdeacf";

        int i=FirstRepeated(s);

        if (i!=-1)

           System.out.println("Char = "+ s.charAt(i) + "   and Index = "+i);

        else

            System.out.println( "No repeated Char");

    }

}




OUTPUT

Char = a   and Index = 6

CREDITS: https://www.geeksforgeeks.org/efficiently-find-first-repeated-character-string-without-using-additional-data-structure-one-traversal/