#include<bits/stdc++.h>
using namespace std;
#define int long long
const int M = 1000000005;
int a[500005];
int n,m,k,l;
int val[500005],pos[500005];int h = 0;
vector<int>ll[500005];
int nxt[500005],pre[500005];
vector<int>pp;
struct tree{
	int ls,rs,mx;
}tree[20000005];int nw = 1;
void update(int l,int r,int k,int pos,int add){
	if(l+1 == r){
		tree[k].mx = max(tree[k].mx,add);return;
	}
	int mid = l+r>>1;
	if(pos<mid){
		if(!tree[k].ls)tree[k].ls = ++nw;
		update(l,mid,tree[k].ls,pos,add);
	}else{
		if(!tree[k].rs)tree[k].rs = ++nw;
		update(mid,r,tree[k].rs,pos,add);
	}
	tree[k].mx = max(tree[tree[k].ls].mx,tree[tree[k].rs].mx);
}
int query(int l,int r,int ll,int rr,int k){
	if(!k)return 0;
	if(l<=ll and rr<=r)return tree[k].mx;
	int mid =ll+rr>>1;
	if(l>=mid){
		return query(l,r,mid,rr,tree[k].rs);
	}
	if(r<=mid){
		if(tree[k].ls)return query(l,r,ll,mid,tree[k].ls);
	}
	return max(query(l,r,ll,mid,tree[k].ls),query(l,r,mid,rr,tree[k].rs));
}
int calc(int x){x-=2*k;return (x+k)/(k+1);}
void solve(){
	cin >> n >> m >> k >> l;
	//--------------------------------------------------------------------------
	for(int i = 1;i<=n;i++)cin >> a[i];
	for(int i =0;i<=n+5;i++)ll[i].clear();pp.clear();
	for(int i =0;i<=nw;i++)tree[i].ls = tree[i].rs = tree[i].mx = 0;nw = 1;h =0;
	//--------------------------------------------------------------------------检查!!!!
	/*
	tree把所有节点都清了肯定没问题
	h 每次归零不会有问题
	h最大是 n+3 ll 清空是对的
	nxt 和 pre 每次用之前都清了
	pp clear
	保佑我不要挂多测qwq
	*/
	vector<int>p;for(int i = 1;i<=n;i++)p.push_back(a[i]);
	sort(p.begin(),p.end());p.erase(unique(p.begin(),p.end()),p.end());
	for(int i = 1;i<=n;i++){
		int mx = query(max(1ll,a[i]-k),min(m+1,a[i]+k+1),1,M+1,1);
		update(1,M+1,1,a[i],mx+1);
	}
	int ans = n,nowa = 0;
	pos[++h] = -k,val[h] = l;
	for(int i = 0;i<p.size();i++){
		val[++h] = query(p[i],p[i]+1,1,M+1,1);
		pos[h] = p[i];
	}
	pos[++h] = m+k+1,val[h] = l;
	for(int i = 1;i<=h;i++)pp.push_back(val[i]);pp.push_back(0);
	for(int i = 1;i<h;i++)nowa+=calc(pos[i+1]-pos[i]-1);
	sort(pp.begin(),pp.end());pp.erase(unique(pp.begin(),pp.end()),pp.end());
	for(int i = 1;i<=h;i++)val[i] = lower_bound(pp.begin(),pp.end(),val[i])-pp.begin()+1;
	for(int i = 1;i<=h;i++)ll[val[i]].push_back(i);
	for(int i = 0;i<=h+1;i++)nxt[i] = i+1,pre[i] = i-1;nxt[h+1] = h+1,pre[0] = 0;
	ans+=nowa*(pp[1]-pp[0]);
	for(int i = 2;i<pp.size();i++){
		for(int x:ll[i]){
			int p1 = pos[pre[x]],p2 = pos[nxt[x]],p = pos[x];
			nowa-=calc(p-p1-1)+calc(p2-p-1);
			nowa+=calc(p2-p1-1);
			pre[nxt[x]] = pre[x],nxt[pre[x]] = nxt[x];
		}
		ans+=nowa*(pp[i]-pp[i-1]);
	}
	cout << ans << '\n';
}
signed main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int t;cin >> t;
	while(t--){
		solve();
	}
	return 0;
}/*
1
3 3 1 3
1 3 2
*/