Count Subsets With Even XOR I

Count the number of triplets (i, j, k) with i < j < k from an integer array such that the XOR of the three elements has an even number of set bits in its binary representation. The array length is small enough for a straightforward solution.

Examples
Input: [1,2,3]
Output: 1
Hints

Count Subsets With Even XOR I

Count the number of triplets `(i, j, k)` with `i < j < k` from an integer array such that the XOR of the three elements has an even number of set bits in its binary representation. The array length is small enough for a straightforward solution.