1863 - Sum of All Subset XOR Totals.

Easy

The XOR total of an array is defined as the bitwise XOR of all its elements , or 0 if the array is empty.

• For example, the XOR total of the array [2,5,6] is 2 XOR 5 XOR 6 = 1.

Given an array nums, return the sum of all XOR totals for every subset of nums.

Note: Subsets with the same elements should be counted multiple times.

An array a is a subset of an array b if a can be obtained from b by deleting some (possibly zero) elements of b.

Example 1:

Input: nums = 1,3

Output: 6

Explanation: The 4 subsets of 1,3 are:

• The empty subset has an XOR total of 0.

• 1 has an XOR total of 1.

• 3 has an XOR total of 3.

• 1,3 has an XOR total of 1 XOR 3 = 2.

0 + 1 + 3 + 2 = 6

Example 2:

Input: nums = 5,1,6

Output: 28

Explanation: The 8 subsets of 5,1,6 are:

• The empty subset has an XOR total of 0.

• 5 has an XOR total of 5.

• 1 has an XOR total of 1.

• 6 has an XOR total of 6.

• 5,1 has an XOR total of 5 XOR 1 = 4.

• 5,6 has an XOR total of 5 XOR 6 = 3.

• 1,6 has an XOR total of 1 XOR 6 = 7.

• 5,1,6 has an XOR total of 5 XOR 1 XOR 6 = 2.

0 + 5 + 1 + 6 + 4 + 3 + 7 + 2 = 28

Example 3:

Input: nums = 3,4,5,6,7,8

Output: 480

Explanation: The sum of all XOR totals for every subset is 480.

Constraints:

• 1 <= nums.length <= 12

• 1 <= nums[i] <= 20