Java > Recursion-1 > pairStar (CodingBat Solution)

Problem:

Given a string, compute recursively a new string where identical chars that are adjacent in the original string are separated from each other by a "*".

pairStar("hello") → "hel*lo"
pairStar("xxyy") → "x*xy*y"
pairStar("aaaa") → "a*a*a*a"


Solution:

public String pairStar(String str) {
  if (str.equals("") || str.length() == 1) return str;
  if (str.charAt(0) == str.charAt(1)) 
    return str.charAt(0) + "*" + pairStar(str.substring(1));
  else
    return str.charAt(0) + pairStar(str.substring(1));
}

3 comments:

  1. AnonymousJune 25, 2016 at 7:35 PM

    public String pairStar(String str) {
       if(str.length() < 2)return str;
       return str.charAt(0)
                +(str.charAt(0)==str.charAt(1)?"*":"")
                +pairStar(str.substring(1));
    }

    ReplyDelete
  2. ioannisaDecember 10, 2019 at 3:30 AM

    public String pairStar(String str) {
    if (str.length()<2)
    return str;

    String result = str.substring(0,1);
    if (str.charAt(0) == str.charAt(1))
    result += "*";

    return result + pairStar(str.substring(1));
    }

    ReplyDelete
  3. V.HariharanJuly 14, 2021 at 6:38 PM

    y =ut + ½ft²

    ReplyDelete