ac

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

const int N = 2e6 + 10;
int a[N];

int main(){
int m; cin>>m;
while(m--){
int n, k, d, w;
cin>>n>>k>>d>>w;

	for(int i=0; i<n; i++){
		cin>>a[i];
	}
	
	int cnt = 1;
	int rest = k;
	int now = a[0];
	int end = now + w + d;
	for(int i=0; i<n; i++){
		if(rest > 0 && a[i] >= now && a[i] <= end){
			rest--;
		}
		else if(rest == 0){
			cnt++;
			now = a[i];
			end = now + w + d;
			rest = k-1; 
		}
		else if(a[i] > end){
			cnt++;
			now = a[i];
			end = now + w + d;
			rest = k-1;
		}
	}
	cout << cnt << endl;
}

return 0;

}