Minimum Number of Operations to Make Array XOR Equal to K

Given an array and integer k, determine the minimum number of single-bit flips (you may flip any bit of any element, including leading zeros) required so that the bitwise XOR of all elements equals k. The core challenge is optimizing bit-level toggles across elements (bits can be treated independently) under constraints n ≤ 1e5 and values ≤ 1e6.