938 g

codeforces/938/c.cc

@@ -0,0 +1,127 @@
+#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>
+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());
+}
+
+template <typename... Args>
+void pr(std::format_string<Args...> fmt, Args&&... args) {
+  std::print(fmt, std::forward<Args>(args)...);
+}
+
+template <typename... Args>
+void pr(std::format_string<Args...> fmt) {
+  std::print(fmt);
+}
+
+template <typename... Args>
+void prln(std::format_string<Args...> fmt, Args&&... args) {
+  std::println(fmt, std::forward<Args>(args)...);
+}
+
+template <typename... Args>
+void prln(std::format_string<Args...> fmt) {
+  std::println(fmt);
+}
+
+void prln() {
+  std::println();
+}
+
+void prln(auto const& t) {
+  std::println("{}", t);
+}
+
+using ll = long long;
+using ld = long double;
+template <typename T>
+using vec = std::vector<T>;
+template <typename T, size_t N>
+using arr = std::array<T, N>;
+
+#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()
+//  }}}
+
+void solve() {
+  ll n, k;
+  cin >> n >> k;
+  ll ans = 0;
+  vec<ll> a(n);
+  for (auto& e : a) {
+    cin >> e;
+  }
+
+  ll left = ceil(k / 2.0);
+  for (int i = 0; i < sz<int>(a) && left > 0; ++i) {
+    int take = min(a[i], left);
+    a[i] -= take;
+    left -= take;
+    if (a[i] == 0)
+      ++ans;
+  }
+
+  ll right = k / 2;
+
+  for (int i = sz<int>(a) - 1; i >= 0 && a[i] > 0 && right > 0; --i) {
+    int take = min(a[i], right);
+    a[i] -= take;
+    right -= take;
+    if (a[i] == 0)
+      ++ans;
+  }
+
+  prln("{}", ans);
+
+  // prln("{} left attacks and {} right", left, right);
+  // for (auto x : prefix)
+  //   pr("{} ", x);
+  // prln();
+  // for (auto x : postfix)
+  //   pr("{} ", x);
+  // prln();
+
+  // ll left_sunk = distance(prefix.begin(), upper_bound(all(prefix), left)) -
+  // 1; ll right_sunk =
+  //     distance(postfix.begin(), upper_bound(all(postfix), right)) - 1;
+
+  // prln("{} {} {}", left_sunk, right_sunk, left_sunk + right_sunk);
+  // prln("{}", left_sunk + right_sunk);
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+
+  int t = 1;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}