164 lines
3.3 KiB
C++
164 lines
3.3 KiB
C++
#include <bits/stdc++.h> // {{{
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// https://codeforces.com/blog/entry/96344
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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template <typename T>
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[[nodiscard]] static T MIN() {
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return std::numeric_limits<T>::min();
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}
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template <typename T>
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[[nodiscard]] static T MAX() {
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return std::numeric_limits<T>::max();
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}
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template <typename T>
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[[nodiscard]] static T sc(auto&& x) {
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return static_cast<T>(x);
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}
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template <typename T>
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[[nodiscard]] static T sz(auto&& x) {
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return static_cast<T>(x.size());
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}
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#define prln(...) std::println(__VA_ARGS__)
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#define pr(...) std::print(__VA_ARGS__)
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#ifdef LOCAL
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#define dbgln(...) std::println(__VA_ARGS__)
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#define dbg(...) std::print(__VA_ARGS__)
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#endif
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inline static void NO() {
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prln("NO");
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}
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inline static void YES() {
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prln("YES");
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}
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using ll = long long;
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using ld = long double;
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template <typename T>
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using ve = std::vector<T>;
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template <typename T, size_t N>
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using ar = std::array<T, N>;
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template <typename T1, typename T2>
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using pa = std::pair<T1, T2>;
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template <typename... Ts>
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using tu = std::tuple<Ts...>;
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template <typename... Ts>
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using dq = std::deque<Ts...>;
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template <typename... Ts>
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using qu = std::queue<Ts...>;
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template <typename... Ts>
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using pq = std::priority_queue<Ts...>;
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template <typename... Ts>
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using st = std::stack<Ts...>;
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auto lb = [](auto... args) {
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return std::lower_bound(args...);
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};
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auto ub = [](auto... args) {
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return std::upper_bound(args...);
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};
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#define ff first
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#define ss second
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#define eb emplace_back
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#define pb push_back
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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// }}}
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ve<pa<int, int>> dxdy = {{-1, 0}, {0, 1}, {0, -1}, {1, 0}};
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template <typename T>
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struct union_find {
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public:
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explicit union_find(size_t capacity)
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: par(capacity, 0), rank(capacity, 0), sums(capacity, 0) {
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std::iota(par.begin(), par.end(), 0);
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};
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void join(T u, T v) noexcept {
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u = find(u), v = find(v);
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if (u == v)
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return;
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if (rank[u] < rank[v])
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std::swap(u, v);
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if (rank[u] == rank[v])
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++rank[u];
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// NOTE the double counting + joining before collecting value in the union find
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sums[u] += sums[v];
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par[v] = u;
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}
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void insert(T const& u, T const& val) {
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sums[u] = val;
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}
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[[nodiscard]] T find(T const& u) noexcept {
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if (u != par[u])
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par[u] = find(par[u]);
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return par[u];
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}
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std::vector<T> par;
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std::vector<int> rank;
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std::vector<int> sums;
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};
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void solve() {
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int n, m;
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cin >> n >> m;
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union_find<int> uf(n * m);
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ve<ve<int>> grid(n, ve<int>(m));
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auto index = [&](int r, int c) {
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return r * m + c;
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};
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for (int r = 0; r < n; ++r) {
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for (int c = 0; c < m; ++c) {
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cin >> grid[r][c];
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uf.insert(index(r, c), grid[r][c]);
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}
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}
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for (int r = 0; r < n; ++r) {
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for (int c = 0; c < m; ++c) {
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if (grid[r][c]) {
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for (auto& [dr, dc] : dxdy) {
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auto nr = r + dr, nc = c + dc;
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if (min(nr, nc) >= 0 && nr < n && nc < m && grid[nr][nc]) {
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uf.join(index(r, c), index(nr, nc));
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}
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}
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}
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}
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}
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prln("{}", *max_element(all(uf.sums)));
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}
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int main() { // {{{
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cin.tie(nullptr)->sync_with_stdio(false);
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cin.exceptions(cin.failbit);
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int t = 1;
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cin >> t;
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while (t--) {
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solve();
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}
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return 0;
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}
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// }}}
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