cp/codeforces/938/g.cc

#include <bits/stdc++.h>  // {{{

// https://codeforces.com/blog/entry/96344

#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

using namespace std;

template <typename T>
constexpr T MIN = std::numeric_limits<T>::min();

template <typename T>
constexpr T MAX = std::numeric_limits<T>::max();

template <typename T>
[[nodiscard]] static T sc(auto &&x) {
  return static_cast<T>(x);
}

template <typename T>
[[nodiscard]] static T sz(auto &&x) {
  return static_cast<T>(x.size());
}

template <typename... Args>
void pr(std::format_string<Args...> fmt, Args &&...args) {
  std::print(fmt, std::forward<Args>(args)...);
}

template <typename... Args>
void pr(std::format_string<Args...> fmt) {
  std::print(fmt);
}

template <typename... Args>
void prln(std::format_string<Args...> fmt, Args &&...args) {
  std::println(fmt, std::forward<Args>(args)...);
}

template <typename... Args>
void prln(std::format_string<Args...> fmt) {
  std::println(fmt);
}

void prln() {
  std::println();
}

void prln(auto const &t) {
  std::println("{}", t);
}

using ll = long long;
using ld = long double;
template <typename T>
using vec = std::vector<T>;
template <typename T, size_t N>
using arr = std::array<T, N>;

#define ff first
#define ss second
#define eb emplace_back
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
//  }}}

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;

// https://mirror.codeforces.com/blog/entry/124683

namespace hashing {
using i64 = std::int64_t;
using u64 = std::uint64_t;
static const u64 FIXED_RANDOM =
    std::chrono::steady_clock::now().time_since_epoch().count();

#if USE_AES
std::mt19937 rd(FIXED_RANDOM);
const __m128i KEY1{(i64)rd(), (i64)rd()};
const __m128i KEY2{(i64)rd(), (i64)rd()};
#endif

template <class T, class D = void>
struct custom_hash {};

template <class T>
inline void hash_combine(u64 &seed, T const &v) {
  custom_hash<T> hasher;
  seed ^= hasher(v) + 0x9e3779b97f4a7c15 + (seed << 12) + (seed >> 4);
};

template <class T>
struct custom_hash<T,
                   typename std::enable_if<std::is_integral<T>::value>::type> {
  u64 operator()(T _x) const {
    u64 x = _x;
#if USE_AES
    __m128i m{i64(u64(x) * 0xbf58476d1ce4e5b9u64), (i64)FIXED_RANDOM};
    __m128i y = _mm_aesenc_si128(m, KEY1);
    __m128i z = _mm_aesenc_si128(y, KEY2);
    return z[0];
#else
    x += 0x9e3779b97f4a7c15 + FIXED_RANDOM;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
#endif
  }
};

template <class T>
struct custom_hash<T, std::void_t<decltype(std::begin(std::declval<T>()))>> {
  u64 operator()(T const &a) const {
    u64 value = FIXED_RANDOM;
    for (auto &x : a)
      hash_combine(value, x);
    return value;
  }
};

template <class... T>
struct custom_hash<std::tuple<T...>> {
  u64 operator()(const std::tuple<T...> &a) const {
    u64 value = FIXED_RANDOM;
    std::apply(
        [&value](T const &...args) {
          (hash_combine(value, args), ...);
        },
        a);
    return value;
  }
};

template <class T, class U>
struct custom_hash<std::pair<T, U>> {
  u64 operator()(std::pair<T, U> const &a) const {
    u64 value = FIXED_RANDOM;
    hash_combine(value, a.first);
    hash_combine(value, a.second);
    return value;
  }
};
};  // namespace hashing

#ifdef PB_DS_ASSOC_CNTNR_HPP
template <class Key, class Value = null_type>
using hashtable = gp_hash_table<
    Key, Value, hashing::custom_hash<Key>, std::equal_to<Key>,
    direct_mask_range_hashing<>, linear_probe_fn<>,
    hash_standard_resize_policy<hash_exponential_size_policy<>,
                                hash_load_check_resize_trigger<>, true>>;

#endif
#ifdef PB_DS_TREE_POLICY_HPP
template <typename T>
using multiset = tree<T, null_type, std::less_equal<T>, rb_tree_tag,
                      tree_order_statistics_node_update>;
template <class Key, class Value = null_type>
using rbtree = tree<Key, Value, std::less<Key>, rb_tree_tag,
                    tree_order_statistics_node_update>;
#endif

void solve() {
  int n, m;
  cin >> n >> m;

  vec<vec<int>> grid(n, vec<int>(m));

  for (auto &row : grid) {
    for (auto &cell : row)
      cin >> cell;
  }

  int x = gcd(grid[n - 1][m - 1], grid[0][0]);

  vec<int> one, two;
  for (int i = 1; i * i <= x; ++i) {
    if (x % i == 0) {
      one.eb(i);
      if (i != x / i) {
        two.eb(x / i);
      }
    }
  }

  vec<vec<bool>> dp(n, vec<bool>(m, false));

  auto DP = [&](int factor) -> bool {
    for (int i = 0; i < sz<int>(dp); ++i)
      dp[i].assign(m, false);
    dp[0][0] = grid[0][0] % factor == 0;

    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < m; ++j) {
        if (grid[i][j] % factor) {
          continue;
        }
        if (j)
          dp[i][j] = dp[i][j] || dp[i][j - 1];
        if (i)
          dp[i][j] = dp[i][j] || dp[i - 1][j];
      }
    }

    return dp[n - 1][m - 1];
  };

  for (auto it = two.begin(); it != two.end(); ++it) {
    if (DP(*it)) {
      prln("{}", *it);
      return;
    }
  }

  for (auto it = one.rbegin(); it != one.rend(); ++it) {
    if (DP(*it)) {
      prln("{}", *it);
      return;
    }
  }
}

int main() {  // {{{
  cin.tie(nullptr)->sync_with_stdio(false);

  int t = 1;
  cin >> t;

  while (t--) {
    solve();
  }

  return 0;
}
// }}}