codeforces: 1003

codeforces/1003/c.cc

@@ -0,0 +1,106 @@
+//  {{{
+#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>;
+
+#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() {
+  int n, m;
+  cin >> n >> m;
+  vec<int> a(n);
+  for (auto& e : a)
+    cin >> e;
+  int x;
+  cin >> x;
+
+  a[0] = min(a[0], x - a[0]);
+  for (int i = 1; i < n; ++i) {
+    if (a[i] >= a[i - 1] && x - a[i] >= a[i - 1]) {
+      a[i] = min(a[i], x - a[i]);
+    } else if (a[i] >= a[i - 1]) {
+      ;
+    } else if (x - a[i] >= a[i - 1]) {
+      a[i] = x - a[i];
+    } else {
+      prln("NO");
+      return;
+    }
+  }
+  prln("YES");
+}
+
+// {{{
+int main() {
+  cin.tie(nullptr)->sync_with_stdio(false);
+
+  int t = 1;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}