gistfile1.java

public boolean hassum(int target) {
	return hassum_recursive(-1, 0, 0, target);
}

private boolean hassum_recursive(int hi, int lo, int sum, int target) {
	if (sum == target) {
		return true;
	} else if (sum > target && lo < hi) {
		return hassum_recursive(hi, lo + 1, sum - array[lo], target);
	} else {
		int next = hi + 1;
		return (next < array.length) &&
		       hassum_recursive(next, lo, sum + array[next], target);
	}
}