spoj#SUBSUMS. Subset Sums
Subset Sums
Given a sequence of N (1 ≤ N ≤ 34) numbers S1, ..., SN (-20,000,000 ≤ Si ≤ 20,000,000), determine how many subsets of S (including the empty one) have a sum between A and B (-500,000,000 ≤ A ≤ B ≤ 500,000,000), inclusive.
Input
The first line of standard input contains the three integers N, A, and B. The following N lines contain S1 through SN, in order.
Output
Print a single integer to standard output representing the number of subsets satisfying the above property. Note that the answer may overflow a 32-bit integer.
Example
Input: 3 -1 2 1 -2 3 Output: 5
The following 5 subsets have a sum between -1 and 2:
- 0 = 0 (the empty subset)
- 1 = 1
- 1 + (-2) = -1
- -2 + 3 = 1
- 1 + (-2) + 3 = 2