func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   long long size(const T& x) {     return x.size();   }   template <class T>   T smod(T a, T b) {     return (a % b + b) % b;   }   long long n, k;   vector<long long> X;   vector<pair<long long, pair<long long, long long> > > A;   vector<vector<long long> > mem;   long long dp(int at, int chosen) {     if (at >= n) return 0;     if (mem[at][chosen] != -1) return mem[at][chosen];     long long mx = 0;     if (chosen < 2) {       mx = max(mx, A[at].first + dp(A[at].second.second + 1, chosen + 1));     }     mx = max(mx, dp(at + 1, chosen));     return mem[at][chosen] = mx;   }   void solve() {     cin >> n >> k;     mem = vector<vector<long long> >(n + 10, vector<long long>(3, -1));     X = vector<long long>(n);     A = vector<pair<long long, pair<long long, long long> > >(n);     for (long long i = (0); i < (n); ++i) {       cin >> X[i];     }     sort(X.begin(), X.end());     for (long long i = (0); i < (n); ++i) {       long long a;       cin >> a;     }     for (long long i = (0); i < (n); ++i) {       auto r = upper_bound(X.begin(), X.end(), X[i] + k);       int index = r - X.begin() - 1;       A[i] = pair<long long, pair<long long, long long> >(           index - i + 1, pair<long long, long long>(i, index));     }     cout << dp(0, 0) << endl;   }   int main() {     cin.sync_with_stdio(false);     cin.tie(nullptr);     cout.tie(nullptr);     long long t;     cin >> t;     while (t--) solve();   }   