Xor are perioada 4

// https://www.geeksforgeeks.org/calculate-xor-1-n/
int Xor(int N) {
    switch(N & 3) {
        case 0:
            return N;
        case 1:
            return 1;
        case 2:
            return N + 1;
        default:
            return 0;
    }
}