#include<bits/stdc++.h>
#define int long long
#define rg register
#define il inline
#define TT(T, Args) template<typename T, typename... Args>
#define L(i, a, b) for (rg int i = (a); i <= (b); i++)
#define R(i, a, b) for (rg int i = (a); i >= (b); i--)
#define rep(i, a) for (rg auto i : a)
using namespace std;
namespace xmpl_{
	il int rd(){
		int f = 1, x = 0;
		char ch = getchar();
		while(ch < '0' || ch > '9'){
			if (ch == '-') f = -1;
			ch = getchar();
		}
		while(ch >= '0' && ch <= '9'){
			x = x * 10 + ch - '0';
			ch = getchar();
		}
		return x * f;
	}
	TT(T, Args) il void rd(T &x){
		int f = 1;
		x = 0;
		char ch = getchar();
		while(ch < '0' || ch > '9'){
			if (ch == '-') f = -1;
			ch = getchar();
		}
		while(ch >= '0' && ch <= '9'){
			x = x * 10 + ch - '0';
			ch = getchar();
		}
		x *= f;
	}
	TT(T, Args) il void rd(T &x, Args &...args){rd(x), rd(args...);}
	TT(T, Args) il void rdArr(T *arr, int cnt){while(cnt--) rd(*arr), arr++;}
	il void wt(int x){
		if (x < 0){
			putchar('-');
			x = -x;
		}
		if (x > 9) wt(x / 10);
		putchar(x % 10 + 48);
	}
	il void wtln(int x){wt(x), putchar('\n');}
	il void wtsp(int x){wt(x), putchar(' ');}
	il void swap(int &x, int &y){x ^= y ^= x ^= y;}
	il int max(int x, int y){return (x > y ? x : y);}
	il int min(int x, int y){return (x < y ? x : y);}
	il void ckmax(int &x, int y){x = max(x, y);}
	il void ckmin(int &x, int y){x = min(x, y);}
	il void cksum(int &x, int y){x += y;}
	TT(T, Args) il void ckmax(T &x, T y, Args &...args){ckmax(x, y), ckmax(x, args...);}
	TT(T, Args) il void ckmin(T &x, T y, Args &...args){ckmin(x, y), ckmin(x, args...);}
	TT(T, Args) il void cksum(T &x, T y, Args &...args){cksum(x, y), cksum(x, args...);}
}
using namespace xmpl_;
using namespace std;

const int N = 1e6 + 5, M = 21, K = 2e6 + 5, inf = 0x3f3f3f3f3f3f3f3f;
int n, m, k, c, s, ans, a[N];

il void init(){

}

il void clear(){
	
}

il void work(){
	rd(n, m, k, c), rdArr(a + 1, n);
	if (c == 1){
		L(i, 1, n){
			ans += a[i] / k, a[i] %= k;
			if (a[i]){
				ans++;
				int nw = k;
				L(j, i, min(n, i + m - 1)){
					if (!nw) break;
					a[j] -= min(a[j], nw), nw -= min(a[j], nw);
				}
			}
		}
		wt(ans);
		return ;
	}
	cout << "MSYAKIOI";
}

signed main(){
	// #define file 114514
#ifdef file	
	freopen("code.in", "r", stdin);
	freopen("code.out", "w", stdout);
#endif
	// init();
	int t = 1;
	t = rd();
	while(t--){
		clear();
		work();
		puts("");
	}
	return 0;
}