Give Me My Vector

I am in a hurry. I have nnn 2D vectors. And I have created all possible subsets of these nnn vectors. For each of these subsets, I have determined the sum of the vectors in that set. Now, I have 2n2^n2n vectors in front of me. I am not really interested in all of them. I just want to lexicographically sort all these vectors and then pick the kkkth smallest one. As I am in a rush, you will have to do this task for me.

This is a companion discussion topic for the original entry at