//OccDreamer
#include<bits/stdc++.h>

#define vc vector
#define db double
#define fi first
#define se second
#define ll long long
#define mk make_pair
#define pb push_back
#define RI register int
#define PI pair<int,int>
#define ull unsigned long long
#define err cerr << "   -_-   " << endl
#define debug cerr << " ------------------- " << endl

#define input(x) freopen(#x".in","r",stdin)
#define output(x) freopen(#x".out","w",stdout)

#define NO puts("No")
#define YES puts("Yes")

//#define OccDreamer
#define int long long

using namespace std;

namespace IO{
	inline int read(){
		int X=0, W=0; char ch=getchar();
		while(!isdigit(ch)) W|=ch=='-', ch=getchar();
		while(isdigit(ch)) X=(X<<1)+(X<<3)+(ch^48), ch=getchar();
		return W?-X:X;
	}
	inline void write(int x){
		if(x<0) x=-x, putchar('-');
		if(x>9) write(x/10);
		putchar(x%10+'0');
	}
	inline void sprint(int x){write(x), putchar(32);}
	inline void eprint(int x){write(x), putchar(10);}
}using namespace IO;

const int MAXN = 2e5+5;
const int inf = 1e9;

int n, m, k, l, a[MAXN], b[MAXN], nodecnt, tot;
int root, lc[MAXN*33], rc[MAXN*33], maxn[MAXN*33], val[MAXN<<2];

map<int,int> dp;

inline int ask(int now, int l, int r, int L, int R){
	if(!now) return 0;
	if(L<=l && r<=R) return maxn[now];
	int mid=(l+r)>>1, res=0;
	if(L<=mid) res=max(res,ask(lc[now],l,mid,L,R));
	if(R>mid) res=max(res,ask(rc[now],mid+1,r,L,R));
	return res;
}

inline void upd(int &now, int l, int r, int pos, int v){
	if(!now) now=++nodecnt, lc[now]=rc[now]=maxn[now]=0;
	if(l==r) return maxn[now]=v, void();
	int mid=(l+r)>>1;
	pos<=mid?upd(lc[now],l,mid,pos,v):upd(rc[now],mid+1,r,pos,v);
	return maxn[now]=max(maxn[lc[now]],maxn[rc[now]]), void();
}

inline void pushup(int p){
	val[p]=max(val[p<<1],val[p<<1|1]);
	return ;	
}

inline void build(int p, int l, int r){
	if(l==r) return val[p]=dp[b[l]], void();
	int mid=(l+r)>>1;
	build(p<<1,l,mid); build(p<<1|1,mid+1,r);
	return pushup(p);	
}

inline int query(int p, int l, int r, int L, int R){
	if(L>R) return 0; 
	if(L<=l && r<=R) return val[p];
	int mid=(l+r)>>1, res=0;
	if(L<=mid) res=max(res,query(p<<1,l,mid,L,R));
	if(R>mid) res=max(res,query(p<<1|1,mid+1,r,L,R));
	return res;
}

int maxval, node, all;

vc<int> posv[MAXN<<2];

inline void getpos(int p, int l, int r, int L, int R, int v, int idx){
	if(val[p]<v || L>R) return ;
	if(L<=l && r<=R){
		if(l==r) return posv[idx].pb(b[l]), void();
		int mid=(l+r)>>1;
		getpos(p<<1,l,mid,L,R,v,idx); getpos(p<<1|1,mid+1,r,L,R,v,idx);
		return ;
	}
	int mid=(l+r)>>1;
	if(L<=mid) getpos(p<<1,l,mid,L,R,v,idx);
	if(R>mid) getpos(p<<1|1,mid+1,r,L,R,v,idx);
	return ;
}

inline void Query(int idx, int l, int r){
	posv[idx].clear(); posv[idx].shrink_to_fit();
	l=lower_bound(b+1,b+1+(tot+1),l)-b; r=upper_bound(b+1,b+1+(tot+1),r)-b-1;
	if(l>r) maxval=0;
	else{
		maxval=query(1,1,tot,l,r);
		getpos(1,1,tot,l,r,maxval,idx);
	}
}	

inline ll solve(int L, int R, int l, int r, int las){
	if(l>r) return 0;
	int idx=++node; Query(idx,l,r); int w=maxval;
	int cl, cr;
	if(L) cl=l+k;
	else cl=l;
	if(R) cr=r-k;
	else cr=r;
	if(maxval==0){
		if(cl<=cr){
			int c=(cr-cl)/(k+1)+1;
			return 1ll*c*las;
		}
		return 0;
	}
	ll Add;
	if(cl>cr) Add=0;
	else Add=1ll*(las-w)*((cr-cl)/(k+1)+1);
	PI stateL=mk(l,L);
	for(auto i:posv[idx]){
		Add+=solve(stateL.se,1,stateL.fi,i-1,w);
		stateL=mk(i+1,1);	
	}
	Add+=solve(stateL.se,R,stateL.fi,r,w);
	return Add;
}

inline void solve(){
	dp.clear(); int val; 
	root=0; node=0; nodecnt=0;
	n=read(), m=read(), k=read(), l=read();
	if(n==0){
		int c=(m-1)/(k+1)+1;
		return eprint(1ll*c*l), void();
	}
	for(int i=1;i<=n;++i){
		a[i]=read(), val=ask(root,1,m,max(a[i]-k,1ll),min(a[i]+k,m))+1;
		upd(root,1,m,a[i],val); dp[a[i]]=val, b[i]=a[i];
	}
	sort(b+1,b+1+n); tot=unique(b+1,b+1+n)-b-1; build(1,1,tot);	b[tot+1]=2e9;
	eprint(solve(0,0,1,m,l)+n);
}

signed main(){
	int t=read();
	while(t--) solve();
	return 0;
}