Code RoomSubset XOR count
MediumPrep Room Coding #1392

Subset XOR count

CodingAlgorithms & data structuresMid–Senior~25 min

Given a small array of non-negative integers and a target value, count how many subsets (including the empty subset) have a bitwise XOR exactly equal to the target. Values fit in a modest bit width. Use a DP over a dictionary mapping achievable XOR values to their subset counts, processing one element at a time (each element either toggles into the XOR or is skipped). The empty subset has XOR 0.

Implement
count_xor_subsets(nums: list[int], target: int) → int
Examples
in[[1,2,3],0]out2
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 25 min
InputExpectedGot
[[1,2,3],0]2not run yetsample