feat(codeforces/817): ak

codeforces/817/f.cc

@@ -0,0 +1,139 @@
+#include <bits/stdc++.h>  // {{{
+
+#include <algorithm>
+
+// https://codeforces.com/blog/entry/96344
+
+#pragma GCC optimize("O2,unroll-loops")
+#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
+
+using namespace std;
+
+using i32 = int32_t;
+using u32 = uint32_t;
+using i64 = int64_t;
+using u64 = uint64_t;
+using f64 = double;
+using f128 = long double;
+
+#if __cplusplus >= 202002L
+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());
+}
+#endif
+
+static void NO() {
+  std::cout << "NO\n";
+}
+
+static void YES() {
+  std::cout << "YES\n";
+}
+
+template <typename T>
+using vec = std::vector<T>;
+
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define ff first
+#define ss second
+
+#ifdef LOCAL
+#define db(...) std::print(__VA_ARGS__)
+#define dbln(...) std::println(__VA_ARGS__)
+#else
+#define db(...)
+#define dbln(...)
+#endif
+//  }}}
+
+bitset<50 * 50 + 1> visited;
+
+void solve() {
+  const i32 dr8[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
+  const i32 dc8[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
+  u32 n, m;
+  cin >> n >> m;
+  vec<string> g(n);
+  for (auto& s : g)
+    cin >> s;
+  vec<vec<u32>> vis(n, vec<u32>(m, 0));
+  bool ok = true;
+  for (i32 r = 0; r < (i32)n && ok; ++r)
+    for (i32 c = 0; c < (i32)m && ok; ++c)
+      if (g[r][c] == '*' && !vis[r][c]) {
+        vec<pair<i32, i32>> comp;
+        vec<pair<i32, i32>> q = {{r, c}};
+        vis[r][c] = 1;
+        for (i32 qi = 0; qi < (i32)q.size(); ++qi) {
+          auto [x, y] = q[qi];
+          comp.push_back({x, y});
+          for (i32 d = 0; d < 8; ++d) {
+            i32 nx = x + dr8[d], ny = y + dc8[d];
+            if (0 <= nx && nx < (i32)n && 0 <= ny && ny < (i32)m &&
+                g[nx][ny] == '*' && !vis[nx][ny]) {
+              vis[nx][ny] = 1;
+              q.push_back({nx, ny});
+            }
+          }
+        }
+        if (comp.size() != 3) {
+          ok = false;
+          break;
+        }
+        vec<i32> rows, cols;
+        for (auto [x, y] : comp) {
+          rows.push_back(x);
+          cols.push_back(y);
+        }
+        sort(rows.begin(), rows.end());
+        rows.erase(unique(rows.begin(), rows.end()), rows.end());
+        sort(cols.begin(), cols.end());
+        cols.erase(unique(cols.begin(), cols.end()), cols.end());
+        if (rows.size() != 2 || cols.size() != 2) {
+          ok = false;
+          break;
+        }
+        i32 cnt = 0;
+        for (i32 i = 0; i < 2; ++i)
+          for (i32 j = 0; j < 2; ++j)
+            for (auto [x, y] : comp)
+              if (x == rows[i] && y == cols[j])
+                ++cnt;
+        if (cnt != 3) {
+          ok = false;
+          break;
+        }
+      }
+  if (ok)
+    YES();
+  else
+    NO();
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit);
+
+  u32 tc = 1;
+  cin >> tc;
+
+  for (u32 t = 0; t < tc; ++t) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}