code: public static int lastIndexOf(String input, char ch, int offset) {
          for (int i = input.length() - 1 - offset; i >= 0; i--) {
              if (input.charAt(i) == ch) {
                  return i;
              }
          }
          return -1;
      }
docs: Like a String.lastIndexOf but without MIN_SUPPLEMENTARY_CODE_POINT handling
  
  @param input  to check the indexOf on
  @param ch     character to find the index of
  @param offset offset to start the reading from the end
  @return index of the character, or -1 if not found