feat(cf): 894

codeforces/891/f.cc

@@ -0,0 +1,223 @@
+#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>
+[[nodiscard]] static T MIN() {
+  return std::numeric_limits<T>::min();
+}
+
+template <typename T>
+[[nodiscard]] static T MAX() {
+  return 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());
+}
+
+#define prln(...) std::println(__VA_ARGS__)
+#define pr(...) std::print(__VA_ARGS__)
+
+#ifdef LOCAL
+#define dbgln(...) std::println(__VA_ARGS__)
+#define dbg(...) std::print(__VA_ARGS__)
+#endif
+
+inline static void NO() {
+  prln("NO");
+}
+
+inline static void YES() {
+  prln("YES");
+}
+
+using ll = long long;
+using ld = long double;
+template <typename T>
+using ve = std::vector<T>;
+template <typename T, size_t N>
+using ar = std::array<T, N>;
+template <typename T1, typename T2>
+using pa = std::pair<T1, T2>;
+template <typename... Ts>
+using tu = std::tuple<Ts...>;
+template <typename... Ts>
+using dq = std::deque<Ts...>;
+template <typename... Ts>
+using qu = std::queue<Ts...>;
+template <typename... Ts>
+using pq = std::priority_queue<Ts...>;
+template <typename... Ts>
+using st = std::stack<Ts...>;
+
+#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 multitree = 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;
+  cin >> n;
+  ve<ll> a(n);
+  hashtable<ll, ll> freq;
+  for (auto &e : a) {
+    cin >> e;
+    ++freq[e];
+  }
+  int q;
+  cin >> q;
+  while (q--) {
+    ll x, y;
+    cin >> x >> y;
+
+    if (x * x < 4 * y) {
+      pr("0 ");
+      continue;
+    }
+
+    ll root = sqrtl(powl(x, 2) - 4 * y);
+
+    ll r0 = (x + root) / 2;
+    ll r1 = (x - root) / 2;
+
+    if (r0 + r1 != x || r0 * r1 != y) {
+      pr("0 ");
+      continue;
+    }
+
+    if (r0 == r1) {
+      pr("{} ", (freq[r0] - 1) * freq[r0] / 2);
+    } else
+      pr("{} ", freq[r0] * freq[r1]);
+  }
+  prln();
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit);
+
+  int t = 1;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}