private Deque<Character> dequeFrom(CharSequence in){
  if (in == null) {
    return null;
  }
  final Deque<Character> out=new ArrayDeque<>(in.length());
  for (int i=in.length() - 1; i >= 0; i--) {
    out.push(in.charAt(i));
  }
  return out;
}

private Deque < Character > dequeFrom ( CharSequence in ) { if ( in == null ) { return null ; } final Deque < Character > out = new ArrayDeque < > ( in . length ( ) ) ; for ( int i = in . length ( ) - 1 ; i >= 0 ; i -- ) { out . push ( in . charAt ( i ) ) ; } return out ; }
creates deque ( double - side queue ) of charsequence
