SUBSET SUM problem in CODEX 2014

general
1

Problem link : http://www.codechef.com/CODX2014/problems/REN2013D

Please help me how to solve this problem and how this problem is different from standard subset sum problem(NP PROBLEM).The only way i was able to think is : check for each element from low to high that whether any subset whose sum is equal to it exists or not by using the recursive or dp approach.

2

Check Forbidden sum editorial in last long challenge.It’s idea is similar.

3

A brief solution outline can be found here http://discuss.codechef.com/questions/37595/codex-editorials-for-specopssubset-sum