#include <bits/stdc++.h>
using namespace std;
template <typename T>
struct outputer;
struct outputable {};
template <typename T>
inline auto sqr(T x) -> decltype(x * x) {
  return x * x;
}
template <typename T1, typename T2>
inline bool umx(T1& a, T2 b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T1, typename T2>
inline bool umn(T1& a, T2 b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
const int N = 200000;
struct Input {
  int n;
  int a[N];
  vector<int> e[N];
  bool read() {
    if (!(cin >> n)) {
      return 0;
    }
    for (int i = int(0); i < int(n); ++i) {
      scanf("%d", &a[i]);
      --a[i];
    }
    for (int i = int(0); i < int(n - 1); ++i) {
      int x, y;
      scanf("%d%d", &x, &y);
      --x;
      --y;
      e[x].emplace_back(y);
      e[y].emplace_back(x);
    }
    return 1;
  }
  void init(const Input& input) { *this = input; }
};
struct Data : Input {
  int ans;
  void write() { cout << ans << endl; }
};
namespace Main {
struct Solution : Data {
  int mx;
  array<int, 2> calc(int v, int pr) {
    array<int, 2> res{0, 0};
    if (a[v] != -1) {
      res[a[v]] = 1;
    }
    for (int to : e[v]) {
      if (to == pr) {
        continue;
      }
      array<int, 2> cur = calc(to, v);
      for (int t = int(0); t < int(2); ++t) {
        umx(mx, res[t] + cur[!t]);
      }
      for (int t = int(0); t < int(2); ++t) {
        umx(res[t], cur[t]);
        if (a[v] == t) {
          umx(res[t], cur[!t] + 1);
        }
      }
    }
    for (int t = int(0); t < int(2); ++t) {
      umx(mx, res[t]);
    }
    return res;
  }
  void solve() {
    mx = 0;
    calc(0, -1);
    ans = mx / 2 + 1;
  }
  void clear() {
    for (int i = int(0); i < int(n); ++i) {
      e[i] = vector<int>();
    }
  }
};
}  // namespace Main
Main::Solution sol;
int main() {
  cout.setf(ios::showpoint | ios::fixed);
  cout.precision(20);
  int t;
  cin >> t;
  for (int i = int(0); i < int(t); ++i) {
    sol.read();
    sol.solve();
    sol.write();
    sol.clear();
  }
  return 0;
}
