Trello.java

public class Trello {
	public static void main(String[] args){
		divide_and_conquer(491454843L, "acdegilmnoprstuw", 5);
	}

	public static void divide_and_conquer(long target, String letters, int size) {
		char[] test = new char[size];
		for (int index = 0; index < size; index++)
			test[index] = 'a';

		int it = 1;
		do {
			String string = new String(test);
			long hash = hash(string, letters);
			long diff = target - hash;
			System.out.println((it++) + ": " + string + " h:" + hash + " d:" + diff);
			if (diff == 0) {
				System.out.println("success!");
				break;
			}
			for (int index = (test.length - 1); index >= 0; index--) {
				double max = Math.pow(37, index);
				if (diff >= max) {
					int mod = test.length - 1 - index;
					int letter = letters.indexOf(test[mod]) + 1;
					test[mod] = letters.charAt(letter);
					break;
				}
			}
		} while(true);
	}

	private static long hash(String string, String letters) {
		long h = 7;

		for (int i = 0; i < string.length(); i++ ) {
			h = (h * 37 + letters.indexOf(string.charAt(i)));
		}

		return h;
	}
}