#define rep(i, n) for (int i = 0; i < (n); ++i)
class Solution {
public:
    int beautifulSubsets(vector<int>& nums, int k) {
        int n = nums.size();
        vector<int> invalid(n);
        rep(i, n)rep(j, n) {
            if (abs(nums[i]-nums[j]) == k) invalid[i] |= 1<<j;
        }
        int res = 0;
        for (int s = 1; s < (1<<n); ++s) {
            bool ok = true;
            rep(i, n) if (s>>i&1) {
                if (s&invalid[i]) ok = false;
            }
            if (ok) res++;
        }
        return res;
    }
};