All Subsets

Given an array nums of distinct integers, return every subset of nums (its power set), including the empty subset and nums itself.

To make the answer unique, return the subsets in the following canonical order:

• Sort the elements of nums in ascending order; call the sorted values $s_0 < s_1 < \dots < s_{n-1}$.
• There are exactly $2^n$ subsets. List them in the order of the integers $m = 0, 1, \dots, 2^n - 1$: subset $m$ contains $s_i$ exactly when bit $i$ of $m$ (the $2^i$ place) is set.
• Within each subset, list the elements in ascending order.

Under this rule the empty subset comes first and the full sorted array comes last.

Examples

Example 1

Input: nums = [1,2,3]
Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]
Explanation: With s = [1,2,3], subset m is chosen by the set bits of m: m=0 -> [], m=1 -> [1], m=2 -> [2], m=3 -> [1,2], m=4 -> [3], m=5 -> [1,3], m=6 -> [2,3], m=7 -> [1,2,3].

Example 2

Input: nums = [0]
Output: [[],[0]]
Explanation: The only subsets are the empty subset and {0}.