feat(codeforces/995): a-e

codeforces/995/d.cc

@@ -0,0 +1,101 @@
+#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;
+
+using i32 = int32_t;
+using u32 = uint32_t;
+using i64 = int64_t;
+using u64 = uint64_t;
+using d64 = double;
+using d128 = long double;
+template <typename T>
+using vec = std::vector<T>;
+template <typename T, size_t N>
+using arr = std::array<T, N>;
+template <typename T1, typename T2>
+using pai = std::pair<T1, T2>;
+
+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());
+}
+
+static void NO() {
+  std::cout << "NO\n";
+}
+
+static void YES() {
+  std::cout << "YES\n";
+}
+
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+
+#ifdef LOCAL
+#define db(...) std::print(__VA_ARGS__)
+#define dbln(...) std::println(__VA_ARGS__)
+#else
+#define db(...)
+#define dbln(...)
+#endif
+//  }}}
+
+void solve() {
+  u64 n;
+  i64 x, y;
+  cin >> n >> x >> y;
+  vec<i64> a(n);
+  i64 total = 0;
+  for (auto& e : a) {
+    cin >> e;
+    total += e;
+  }
+  sort(all(a));
+
+  auto count = [&](i64 target) {
+    i64 ans = 0;
+    i32 j = n - 1;
+    for (i32 i = 0; i < n; ++i) {
+      while (j > i && a[i] + a[j] > target) {
+        --j;
+      }
+      if (j > i) {
+        ans += j - i;
+      }
+    }
+    return ans;
+  };
+
+  cout << count(total - x) - count(total - y - 1) << '\n';
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit);
+
+  int tc = 1;
+  cin >> tc;
+
+  for (int t = 0; t < tc; ++t) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}