Question

Write a recursive function (static method) called removeCopies that takes a String as a parameter and replaces any copies of the same character with a single occurrence of the character. Your function must be recursive (no loops). For example:

removeCopies(“abccd”) => “abcd”

removeCopies(“xxxxxxx”) => “x”

removeCopies(“xxxyyzaaxxx”) => “xyzax”

Answer 1

public class RemoveCopies {

    public static String removeCopies(String s) {
        if (s.isEmpty() || s.length() == 1) {
            return s;
        } else {
            if (s.charAt(0) != s.charAt(1)) {
                return s.charAt(0) + removeCopies(s.substring(1));
            } else {
                return removeCopies(s.substring(1));
            }
        }
    }

    public static void main(String[] args) {
        System.out.println(removeCopies("abccd"));
        System.out.println(removeCopies("xxxxxxx"));
        System.out.println(removeCopies("xxxyyzaaxxx"));
    }
}