Transform String - JAVA

// Author : Saurav Kalsoor
// Transform String - JAVA

import java.util.*;

public class Test {

    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        String str = sc.next();
        System.out.println(transformString(str));

    }

    public static String transformString(String str){
        if(str.length() == 2) return str;

        int n = str.length();
        String newStr = "";
        for(int i = 0; i < n; i += 2){
            if(i == n - 1){
                newStr += str.charAt(i);
            }else{
                newStr += getAverage(str.charAt(i), str.charAt(i + 1));
            }
        }
        return transformString(newStr);
    }

    public static char getAverage(char a, char b){
        int avg = ((a - 'a') + (b - 'a'))/2;
        return (char)(avg + 'a');
    }

}