E. Two Platforms

#include <bits/stdc++.h>
using namespace std;
#define OO INT_MAX

const int N = 2e5 + 5e2;
int Memo[N][2][2];
vector< int > x;
int n ,k ,y;

/// ------------- Memo[i][F][S] ------------ ///
/// --- i = Index -------------------------- ///
/// --- F = If First Platform Used Or Not -- ///
/// --- S = If Second Platform Used Or Not - ///

int Calc(int i ,bool F ,bool S){
    if( i == n ) return 0;

    int & Re = Memo[i][F][S];
    if( Re  +  1 ) return Re;

    Re = -OO;
    int EdP    = x[i] + k; /// --- End Position --- //
    int newIdx = upper_bound(x.begin() ,x.end() ,EdP) - x.begin();

    Re = max(Re ,Calc(i + 1 ,F ,S));                    // Try To Put Platform In i + 1
    if( !F ) Re = max(Re ,Calc(newIdx ,true ,S) + (newIdx - i) ); // Try Put F Platform
    if( !S ) Re = max(Re ,Calc(newIdx ,F ,true) + (newIdx - i) ); // Try Put S Platform

    return Re;
}

void Solve(){
    scanf("%d%d" ,&n ,&k); x.resize(n);
    for( auto &i : x ) scanf("%d" ,&i);
    for( auto  i : x ) scanf("%d" ,&i);

    sort(x.begin() ,x.end());

    /// --- Memset(Dp = -1) --- ///
    for(int i = 0 ; i <= n ; i++)
        for(int F = 0 ; F < 2 ; F++)
            for(int S = 0 ; S < 2 ; S++)
                Memo[i][F][S] = -1;

    int Ans = Calc(0 ,false ,false);
    printf("%d\n" ,Ans);
}

int main() {
    int Tc; scanf("%d" ,&Tc);
    while( Tc-- ) Solve();
    return 0;
}