#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
template <class T>
using V = vector<T>;
template <class T, size_t SZ>
using AR = array<T, SZ>;
const int MOD = 1e9 + 7;
const int MX = 5e5 + 5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
const int xd[4] = {1, 0, -1, 0}, yd[4] = {0, 1, 0, -1};
mt19937 rng(0);
constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int bits(int x) { return 31 - __builtin_clz(x); }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
template <class T>
bool ckmin(T& a, const T& b) {
  return b < a ? a = b, 1 : 0;
}
template <class T>
bool ckmax(T& a, const T& b) {
  return a < b ? a = b, 1 : 0;
}
template <class T, class U>
T fstTrue(T lo, T hi, U first) {
  hi++;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo) / 2;
    first(mid) ? hi = mid : lo = mid + 1;
  }
  return lo;
}
template <class T, class U>
T lstTrue(T lo, T hi, U first) {
  lo--;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo + 1) / 2;
    first(mid) ? lo = mid : hi = mid - 1;
  }
  return lo;
}
template <class T>
void remDup(vector<T>& v) {
  sort(begin(v), end(v));
  v.erase(unique(begin(v), end(v)), end(v));
}
template <class T, class U>
void erase(T& t, const U& u) {
  auto it = t.find(u);
  assert(it != end(t));
  t.erase(u);
}
template <class T>
void re(complex<T>& c);
template <class T, class U>
void re(pair<T, U>& p);
template <class T>
void re(vector<T>& v);
template <class T, size_t SZ>
void re(AR<T, SZ>& a);
template <class T>
void re(T& x) {
  cin >> x;
}
void re(db& d) {
  str t;
  re(t);
  d = stod(t);
}
void re(ld& d) {
  str t;
  re(t);
  d = stold(t);
}
template <class T, class... U>
void re(T& t, U&... u) {
  re(t);
  re(u...);
}
template <class T>
void re(complex<T>& c) {
  T a, b;
  re(a, b);
  c = {a, b};
}
template <class T, class U>
void re(pair<T, U>& p) {
  re(p.first, p.second);
}
template <class T>
void re(vector<T>& x) {
  for (auto& a : x) re(a);
}
template <class T, size_t SZ>
void re(AR<T, SZ>& x) {
  for (auto& a : x) re(a);
}
str to_string(char c) { return str(1, c); }
str to_string(const char* second) { return (str)second; }
str to_string(str second) { return second; }
str to_string(bool b) { return to_string((int)b); }
template <class T>
str to_string(complex<T> c) {
  stringstream ss;
  ss << c;
  return ss.str();
}
str to_string(vector<bool> v) {
  str res = "{";
  for (int i = (0); i < ((int)(v).size()); ++i) res += char('0' + v[i]);
  res += "}";
  return res;
}
template <size_t SZ>
str to_string(bitset<SZ> b) {
  str res = "";
  for (int i = (0); i < (SZ); ++i) res += char('0' + b[i]);
  return res;
}
template <class T, class U>
str to_string(pair<T, U> p);
template <class T>
str to_string(T v) {
  bool fst = 1;
  str res = "";
  for (const auto& x : v) {
    if (!fst) res += " ";
    fst = 0;
    res += to_string(x);
  }
  return res;
}
template <class T, class U>
str to_string(pair<T, U> p) {
  return to_string(p.first) + " " + to_string(p.second);
}
template <class T>
void pr(T x) {
  cout << to_string(x);
}
template <class T, class... U>
void pr(const T& t, const U&... u) {
  pr(t);
  pr(u...);
}
void ps() { pr("\n"); }
template <class T, class... U>
void ps(const T& t, const U&... u) {
  pr(t);
  if (sizeof...(u)) pr(" ");
  ps(u...);
}
void DBG() { cerr << "]" << endl; }
template <class T, class... U>
void DBG(const T& t, const U&... u) {
  cerr << to_string(t);
  if (sizeof...(u)) cerr << ", ";
  DBG(u...);
}
void setIn(str second) { freopen(second.c_str(), "r", stdin); }
void setOut(str second) { freopen(second.c_str(), "w", stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str second = "") {
  unsyncIO();
  if ((int)(second).size()) {
    setIn(second + ".in"), setOut(second + ".out");
  }
}
int seg[1 << 20], lazy[1 << 20];
int calc(int ind) { return seg[ind] + lazy[ind]; }
void ad(int mn, int ind, int L, int R) {
  if (mn > R) return;
  if (mn <= L) {
    lazy[ind]++;
    return;
  }
  int M = (L + R) / 2;
  ad(mn, 2 * ind, L, M);
  ad(mn, 2 * ind + 1, M + 1, R);
  seg[ind] = min(calc(2 * ind), calc(2 * ind + 1));
}
vpi pairs;
void build(int ind, int L, int R) {
  lazy[ind] = 0;
  if (L == R) {
    seg[ind] = (int)(pairs).size() - L;
    return;
  }
  int M = (L + R) / 2;
  build(2 * ind, L, M);
  build(2 * ind + 1, M + 1, R);
  seg[ind] = min(calc(2 * ind), calc(2 * ind + 1));
  assert(seg[ind] == (int)(pairs).size() - R);
}
int qmin(int lo, int ind, int L, int R) {
  if (lo <= L) return calc(ind);
  if (R < lo) return MOD;
  int M = (L + R) / 2;
  return min(qmin(lo, 2 * ind, L, M), qmin(lo, 2 * ind + 1, M + 1, R)) +
         lazy[ind];
}
int n;
vi a;
vi zero;
vi todo[MX];
bool ok(int num) {
  pairs.clear();
  for (int i = (0); i < (num); ++i)
    pairs.push_back({zero[i], zero[(int)(zero).size() - num + i]});
  int lo = 0, hi = -1;
  vi LO(n + 1, (int)(pairs).size() + 1), HI(n + 1, 0);
  for (int i = (0); i < (n); ++i)
    if (a[i]) {
      while (lo < (int)(pairs).size() && pairs[lo].second < i) lo++;
      while (hi + 1 < (int)(pairs).size() && pairs[hi + 1].first <= i) hi++;
      if (lo <= hi) {
        if (lo == 0) {
          ckmax(HI[a[i]], hi + 1);
        } else {
          assert(hi == (int)(pairs).size() - 1);
          ckmin(LO[a[i]], lo + 1);
        }
      }
    }
  for (int i = (0); i < ((int)(pairs).size()); ++i) todo[i].clear();
  int abv = 0;
  for (int i = (1); i < (n + 1); ++i) {
    if (HI[i] == 0 && LO[i] == (int)(pairs).size() + 1) continue;
    todo[HI[i]].push_back(LO[i]);
    abv++;
  }
  build(1, 0, (int)(pairs).size());
  for (int i = (0); i < ((int)(pairs).size()); ++i) {
    for (auto& t : todo[i]) {
      abv--;
      ad(t, 1, 0, (int)(pairs).size());
    }
    if (i + abv + qmin(i, 1, 0, (int)(pairs).size()) < (int)(pairs).size()) {
      return 0;
    }
  }
  return 1;
}
void solve() {
  n = rng() % 10 + 1;
  a.clear();
  for (int j = (0); j < (n); ++j) {
    if (rng() & 1)
      a.push_back(0);
    else
      a.push_back(rng() % min(n, 3) + 1);
  }
  re(n);
  a.resize(n);
  re(a);
  zero.clear();
  for (int i = (0); i < (n); ++i)
    if (a[i] == 0) zero.push_back(i);
  int ans1 = lstTrue(1, (int)(zero).size() / 2, [&](int x) { return ok(x); });
  ps(ans1);
}
int main() {
  setIO();
  int t;
  re(t);
  for (int i = (0); i < (t); ++i) solve();
}
