xor_arr[mask] = xor_arr[mask ^ lb] ^ nums[i];

}

int64_t result =0;

vector<int>base(l);

vector<int>base(l);// to improve performance

for (int mask =1; mask < (1 << n); ++mask) {

constauto& total_and = and_arr[mask];

constauto& total_xor = xor_arr[full_mask ^ mask];

base.assign(l,0);// to improve performance

base.assign(l,0);

for (int remain = full_mask ^ mask; remain; remain &= remain -1) {

constint i =__builtin_ctz(remain);

int x = nums[i] & ~total_xor;