#include <bits/stdc++.h>
using namespace std;
using LL = long long;
#define pb emplace_back
#define sz(a) int(a.size())

const int N = 2e5 + 5, M = 3 * N;
int n, m, k, l, a[N];

set<pair<int, int>> S;
vector<int> vec[N], disc, b;

#define mid ((L + R) >> 1)
#define Ls rt << 1, L, mid
#define Rs rt << 1 | 1, mid + 1, R

int tr[M << 2];
void upd(int p, int v, int rt = 1, int L = 1, int R = sz(disc)) {
  if (L == R) {
    tr[rt] = v;
    return ;
  }
  p <= mid ? upd(p, v, Ls) : upd(p, v, Rs);
  tr[rt] = max(tr[rt << 1], tr[rt << 1 | 1]);
}
int qry(int l, int r, int rt = 1, int L = 1, int R = sz(disc)) {
  if (l <= L && R <= r) {
    return tr[rt];
  }
  int res = 0;
  if (l <= mid) {
    res = max(res, qry(l, r, Ls));
  }
  if (r > mid) {
    res = max(res, qry(l, r, Rs));
  }
  return res;
}
void build(int rt = 1, int L = 1, int R = sz(disc)) {
  tr[rt] = 0;
  if (L == R) {
    return ;
  }
  build(Ls), build(Rs);
}

#undef mid
#undef Ls
#undef Rs

inline int askd(int x) {
  return lower_bound(disc.begin(), disc.end(), x) - disc.begin() + 1;
}

inline int calc(int x) {
  return x >= 1 ? (x - 1) / (k + 1) + 1 : 0;
}
inline int calc(set<pair<int, int>>::iterator it) {
  return calc(it->second - it->first + 1 - ((it->first != 1) + (it->second != m)) * k);
}

void work() {
  cin >> n >> m >> k >> l;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    disc.pb(a[i]), disc.pb(max(1, a[i] - k)), disc.pb(min(m, a[i] + k));
    b.pb(a[i]);
  }
  sort(disc.begin(), disc.end());
  disc.erase(unique(disc.begin(), disc.end()), disc.end());
  sort(b.begin(), b.end());
  b.erase(unique(b.begin(), b.end()), b.end());
  for (int i = 1; i <= n; ++i) {
    upd(askd(a[i]), qry(askd(max(1, a[i] - k)), askd(min(m, a[i] + k))) + 1);
  }
  int pre = 1, now = 0;
  for (int v : b) {
    vec[qry(askd(v), askd(v))].pb(v);  
    if (pre < v) {
      now += calc(S.emplace(pre, v - 1).first);
    }
    pre = v + 1;
  }
  if (pre <= m) {
    now += calc(S.emplace(pre, m).first);
  }
  LL ans = n;
  for (int i = 1; i <= tr[1]; ++i) {
    ans += now;
    for (auto v : vec[i]) {
      auto it = S.lower_bound(make_pair(v, 0));
      int l = v, r = v;
      if (it != S.begin() && prev(it)->second == v - 1) {
        l = prev(it)->first, now -= calc(prev(it)), S.erase(prev(it));
      }
      if (it != S.end() && it->first == v + 1) {
        r = it->second, now -= calc(it), S.erase(it);
      }
      now += calc(S.emplace(l, r).first);
    }
  }
  ans += 1ll * (l - tr[1]) * calc(m);
  cout << ans << '\n';
}

void clear() {
  S.clear();
  for (int i = 1; i <= tr[1]; ++i) {
    vector<int>().swap(vec[i]);
  }
  if (sz(disc)) {
    build();
  }
  vector<int>().swap(disc);
  vector<int>().swap(b);
}

signed main() {
  cin.tie(0)->sync_with_stdio(0);
  int test;
  for (cin >> test; test--; ) {
    work(), clear();
  }
  return 0;
}