feat(codeforces): 998

codeforces/998/e.cc

@@ -0,0 +1,185 @@
+#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... Args>
+void dbg(std::string const &str, Args &&...args) {
+  std::cout << std::vformat(str, std::make_format_args(args...));
+}
+
+template <typename T>
+void dbg(T const &t) {
+  std::cout << t;
+}
+
+template <std::ranges::range T>
+void dbgln(T const &t) {
+  if constexpr (std::is_convertible_v<T, char const *>) {
+    std::cout << t << '\n';
+  } else {
+    for (auto const &e : t) {
+      std::cout << e << ' ';
+    }
+    std::cout << '\n';
+  }
+}
+
+void dbgln() {
+  std::cout << '\n';
+}
+
+template <typename... Args>
+void dbgln(std::string const &str, Args &&...args) {
+  dbg(str, std::forward<Args>(args)...);
+  cout << '\n';
+}
+
+template <typename T>
+void dbgln(T const &t) {
+  dbg(t);
+  cout << '\n';
+}
+
+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>
+static T sc(auto &&x) {
+  return static_cast<T>(x);
+}
+
+#define ff first
+#define ss second
+#define eb emplace_back
+#define ll long long
+#define ld long double
+#define vec vector
+#define endl '\n'
+
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (r).rbegin(), (x).rend()
+#define sz(x) static_cast<int>((x).size())
+#define FOR(a, b, c) for (int a = (b); (a) < (c); ++(a))
+#define ROF(a, b, c) for (int a = (b); (a) > (c); --(a))
+
+struct union_find {
+ public:
+  union_find(size_t n = 0) : par(n + 1), rank(n + 1, 0) {
+    for (size_t u = 0; u < n + 1; ++u)
+      par[u] = u;
+  };
+
+  void join(int u, int v) {
+    u = find(u), v = find(v);
+
+    if (u == v)
+      return;
+
+    if (rank[u] < rank[v])
+      std::swap(u, v);
+
+    if (rank[u] == rank[v])
+      ++rank[u];
+
+    par[v] = u;
+  }
+
+  int find(int u) {
+    if (u != par[u])
+      par[u] = find(par[u]);
+    return par[u];
+  }
+
+  void reset(size_t capacity) {
+    par.resize(capacity);
+    std::iota(par.begin(), par.end(), 0);
+    rank.resize(capacity);
+  }
+
+  std::vector<int> par;
+  std::vector<int> rank;
+};
+
+vec<unordered_set<int>> F, G;
+union_find Fuf, Guf;
+unordered_set<int> to_erase;
+
+void solve() {
+  int n, m1, m2;
+  cin >> n >> m1 >> m2;
+
+  F.clear();
+  F.resize(n + 1);
+  G.clear();
+  G.resize(n + 1);
+
+  Fuf.reset(n + 1);
+  Guf.reset(n + 1);
+
+  FOR(i, 0, m1) {
+    int u, v;
+    cin >> u >> v;
+    F[u].insert(v);
+    F[v].insert(u);
+  }
+
+  FOR(i, 0, m2) {
+    int u, v;
+    cin >> u >> v;
+    G[u].insert(v);
+    G[v].insert(u);
+    Guf.join(u, v);
+  }
+
+  int ans = 0;
+
+  FOR(u, 1, n + 1) {
+    to_erase.clear();
+    for (auto v : F[u]) {
+      if (Guf.find(u) != Guf.find(v)) {
+        to_erase.insert(v);
+        F[v].erase(u);
+      }
+    }
+    ans += to_erase.size();
+    for (auto e : to_erase)
+      F[u].erase(e);
+  }
+
+  FOR(u, 1, n + 1) {
+    for (auto v : F[u])
+      Fuf.join(u, v);
+  }
+
+  FOR(u, 1, n + 1) {
+    for (auto v : G[u]) {
+      if (Fuf.find(u) != Fuf.find(v)) {
+        ++ans;
+        Fuf.join(u, v);
+      }
+    }
+  }
+
+  dbgln(ans);
+}
+
+int main() {
+  cin.tie(nullptr)->sync_with_stdio(false);
+
+  int t = 1;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}