gistfile1.java

public static int[] countLetters(String input) {
  int[] results = new int[26];
  for (int i = 0; i < input.length(); i++) {
    int cur = input.toLowerCase().charAt(i);
    if (cur >= 'a' && cur <= 'z') {results[cur - 'a']++;}
  }
  return results;
}