ChangeCounter.java

public class ChangeCounter {

    int cents[] = { 50, 25, 10, 5, 1 };

    public int count(int amount) {
        return count(amount, 0);
    }

    private int count(int amount, int idx) {
        if (amount == 0) {
            return 1;
        } else if (amount < 0 || idx >= cents.length) {
            return 0;
        }
        return count(amount - cents[idx], idx) + count(amount, idx + 1);
    }
}