Generate All Subsets

Given an array of distinct integers, generate every subset (the power set).

Input Format

The first line contains an integer N. The second line contains N space-separated distinct integers.

Output Format

Print 2^N lines, one per subset, in order of the binary mask 0 .. 2^N - 1. For a mask, list the elements at set bit positions in index order, separated by single spaces. The empty subset is printed as an empty line.