Given a string, replace adjacent, repeated characters with the character followed by the number of repeated occurrences. If the character does not has any adjacent, repeated occurrences, it is not changed.

Assumptions

• The string is not null

• The characters used in the original string are guaranteed to be ‘a’ - ‘z’

• There are no adjacent repeated characters with length > 9

Examples

• “abbcccdeee” → “ab2c3de3”

  public String compress(String input) {
    if (input.length() < 2) {
      return input;
    }
    StringBuilder sb = new StringBuilder();
    int count = 1;
    for (int i = 0; i < input.length(); i++) {
      if (i + 1 < input.length() && input.charAt(i) == input.charAt(i + 1)) {
        count++;
        continue;
      }
      sb.append(input.charAt(i));
      if (count > 1) {
        sb.append(count);
        count = 1;
      }
    }
    return sb.toString();
  }