#define sync_cout std::cout << IO_LOCK
#define sync_endl std::endl << IO_UNLOCK
+namespace Utility {
+
+/// Clamp a value between lo and hi. Available in c++17.
+template<class T> constexpr const T& clamp(const T& v, const T& lo, const T& hi) {
+ return v < lo ? lo : v > hi ? hi : v;
+}
+
+}
/// xorshift64star Pseudo-Random Number Generator
/// This class is based on original code written and dedicated