// 1863. Sum of All Subset XOR Totals #include "leetcode.h" /* * 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'. */ void backtrack(int *nums, int numsSize, int tar, int idx, int *cnt) { if (idx == numsSize) { return; } else { for (int i = idx; i < numsSize; i++) { tar ^= nums[i]; *cnt += tar; backtrack(nums, numsSize, tar, i + 1, cnt); tar ^= nums[i]; } } } int subsetXORSum(int *nums, int numsSize) { int ans = 0; for (int i = 0; i < numsSize; i++) { ans += nums[i]; backtrack(nums, numsSize, nums[i], i + 1, &ans); } return ans; } int main() { int n1[] = {1, 3}, n2[] = {5, 1, 6}, n3[] = {3, 4, 5, 6, 7, 8}; printf("%d\n", subsetXORSum(n1, ARRAY_SIZE(n1))); // expect: 6 printf("%d\n", subsetXORSum(n2, ARRAY_SIZE(n2))); // expect: 28 printf("%d\n", subsetXORSum(n3, ARRAY_SIZE(n3))); // expect: 480 }