SUBSUMS  Subset Sums
Given a sequence of N (1 ≤ N ≤ 34) numbers S_{1}, ..., S_{N} (20,000,000 ≤ S_{i} ≤ 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 S_{1} through S_{N}, 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 32bit 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
hide comments
purohit:
20190403 07:03:54
TLE using recurison 

gamapro:
20190402 05:52:05
Nice problem! AC in one go! Binary Search Tree required! 

hieudoan7:
20190124 08:18:45
hay


rik4chu:
20180122 00:50:58
Be careful with the overflow ;) 

imperfectboy:
20170917 08:31:54
learnt alot !! after 2WA and 4TLE finally AC!! 

vengatesh15:
20170914 08:58:41
Meet in the middle.. 

nikhil15150:
20170718 12:48:32
Can anyone please tell me what are some corner test cases ?.Because I am getting wrong Answer. 

heisenberg0820:
20170629 18:13:58
Meet in the middle :) 

bluejam:
20170622 11:02:01
Empty subset should either be considered or not considered in the final value.


coolio_1:
20170621 15:33:03
Nice problem!! Take care whether the empty subset sum lies in the range [a,b] or not.

Added by:  Neal Wu 
Date:  20090119 
Time limit:  0.328s0.657s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO 