[Deque]

Another possibility to initialize the alphabet:

Code:

public static char[] initAllowedCharacters(int start, int end) { char[] allowedCharacters = new char[end - start + 1]; for (int i = start; i <= end; i++) { allowedCharacters[i - start] = (char) i; } return allowedCharacters; }

I.e. for the letters a-z you do:

Code:

char[] alphabet = initAllowedCharacters('a', 'z');