#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
#define fir first
#define sec second
typedef vector <int> vi;
typedef vector <ll> vl;

namespace IO {
const int MAXSIZE = 1 << 20;
char buf[MAXSIZE], *p1, *p2;
#define getchar() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, MAXSIZE, stdin), p1 == p2) ? EOF : *p1++)

char pbuf[MAXSIZE], *pp = pbuf;
void flush() { fwrite(pbuf, 1, pp - pbuf, stdout), pp = pbuf; }
inline void putchar(char ch) {
	if (pp == pbuf + MAXSIZE) flush();
	*pp++ = ch;
}
struct IO { ~IO () { flush(); } } __io;

char stk[40]; int tp;
namespace Public {
template <typename __Tp> void read(__Tp &x) {
	int f = 0; x = 0; char ch = getchar();
	for (; !isdigit(ch); ch = getchar()) if (ch == '-') f = 1;
	for (; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + (ch ^ 48);
	if (f) x = -x;
}
template <typename __Tp1, typename ...__Tp2> void read(__Tp1 &x, __Tp2 &...y) { read(x), read(y...); }
template <typename __Tp> void write(__Tp x) {
	if (x < 0) putchar('-'), x = -x;
	stk[tp = 1] = x % 10 + 48;
	while (x > 9) x /= 10, stk[++tp] = x % 10 + 48;
	while (tp) putchar(stk[tp]), tp--;
}
void write(char ch) { putchar(ch); }
template <typename __Tp1, typename ...__Tp2> void write(__Tp1 x, __Tp2 ...y) { write(x), write(y...); }
}
#undef getchar
}
using namespace IO :: Public;

#ifdef LCX
#define msg(args...) fprintf(stderr, args)
#else
#define msg(...) void()
#endif

const int maxn = 2e5 + 10;
ll n, a[maxn], s[maxn], p[maxn], q[maxn];
vl X;
struct BIT {
	ll c[maxn];
	void clr() { memset(c, 0, sizeof c); }
	void add(ll x, ll y) { for (; x <= n; x += x & -x) c[x] += y; }
	ll ask(ll x) {
		ll res = 0;
		for (; x > 0; x &= x - 1) res += c[x];
		return res;
	}
	ll ask(ll l, ll r) { return ask(r) - ask(l - 1); }
} tr, tr2;
void work() {
	read(n);
	for (int i = 0; i < n; ++i) read(a[i]), s[i] = a[i];
	for (int i = 1; i < n; ++i) s[i] += s[i - 1];

	ll S = s[n - 1];
	if (S < 0) return write(-1, '\n');
	if (S == 0) {
		int flg = 1;
		for (int i = 0; i < n; ++i) flg &= (a[i] == 0);
		if (flg) write(0, '\n');
		else write(-1, '\n');
		return;
	}

	X.clear();
	for (int i = 0; i < n; ++i)
		q[i] = (s[i] % S + S) % S,
		p[i] = (s[i] - q[i]) / S,
		X.push_back(q[i]);
	sort(begin(X), end(X)), X.erase(unique(begin(X), end(X)), end(X));
	for (int i = 0; i < n; ++i) q[i] = lower_bound(begin(X), end(X), q[i]) - begin(X) + 1;

	vi rk(n);
	iota(begin(rk), end(rk), 0);
	sort(begin(rk), end(rk), [&] (int i, int j) { return s[i] < s[j]; });

	ll sump = 0, ans = 0;
	tr.clr(), tr2.clr();
	for (int i = 0, j = 0; i < n; ++i) {
		int u = rk[i];
		msg("%d : %lld\n", u, s[u]);
		while (j < n && s[rk[j]] < s[u]) {
			int v = rk[j];
			msg("add %d\n", v);
			sump += p[v];
			tr.add(q[v], 1);
			tr2.add(v + 1, 1);
			j++;
		}
		ans += p[u] * j - sump + tr.ask(q[u] - 1) - tr2.ask(u);
	}
	write(ans, '\n');
}

int main() {
	// freopen("circle.in", "r", stdin), freopen("circle.out", "w", stdout);
	int T; read(T);
	while (T--) work();
	return 0;
}