Java > Recursion-1 > stringClean (CodingBat Solution)

Problem:

Given a string, return recursively a "cleaned" string where adjacent chars that are the same have been reduced to a single char. So "yyzzza" yields "yza".

stringClean("yyzzza") → "yza"
stringClean("abbbcdd") → "abcd"
stringClean("Hello") → "Helo"

Solution:

public String stringClean(String str) {
  if (str.length() < 2) return str;
  if (str.charAt(0) == str.charAt(1))
    return stringClean(str.substring(1));
  else
    return str.charAt(0) + stringClean(str.substring(1));
}