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# 1863. Sum of All Subset XOR Totals

"""
the xor total of an array is defined as the bitwise xor of all its elements
or 0 if the array is empty. given an array 'nums' return the sum of all xor
totals for every subset of 'nums'. an array 'a' is a subset of an array 'b'
if 'a' can be obtained from 'b' by deleting some elements of 'b'.
"""


class Solution(object):
    def subsetXORSum(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """

        def backtrack(nums, idx, tar, cnt):
            if idx == len(nums):
                cnt.append(tar[:])
                return
            tar.append(nums[idx])
            backtrack(nums, idx + 1, tar, cnt)
            tar.pop()
            backtrack(nums, idx + 1, tar, cnt)

        cnt = []
        backtrack(nums, 0, [], cnt)
        ans = 0
        for i in cnt:
            total = 0
            for n in i:
                total ^= n
            ans += total
        return ans


if __name__ == "__main__":
    obj = Solution()
    print(obj.subsetXORSum(nums=[1, 3]))
    print(obj.subsetXORSum(nums=[5, 1, 6]))
    print(obj.subsetXORSum(nums=[3, 4, 5, 6, 7, 8]))