refactor: rename modint.hpp to mod_utility.hpp

Author: weilycoder

test/primality_test.test.cpp

@@ -14,10 +14,7 @@ int main() {
   while (q--) {
     uint64_t n;
     cin >> n;
-    if (n <= UINT32_MAX)
-      cout << (miller_rabin32(n) ? "Yes\n" : "No\n");
-    else
-      cout << (miller_rabin64(n) ? "Yes\n" : "No\n");
+    cout << (is_prime(n) ? "Yes\n" : "No\n");
   }
   return 0;
 }

weilycoder/number-theory/modint.hpp renamed to weilycoder/number-theory/mod_utility.hpp

@@ -1,9 +1,9 @@
-#ifndef WEILYCODER_MODINT_HPP
-#define WEILYCODER_MODINT_HPP
+#ifndef WEILYCODER_MOD_UTILITY_HPP
+#define WEILYCODER_MOD_UTILITY_HPP
 
 /**
- * @file modint.hpp
- * @brief Modular Integer Arithmetic Utilities
+ * @file mod_utility.hpp
+ * @brief Modular Arithmetic Utilities
  */
 
 #include <cstdint>
@@ -26,6 +26,24 @@ uint64_t modular_multiply_64(uint64_t a, uint64_t b, uint64_t modulus) {
     return static_cast<unsigned __int128>(a) * b % modulus;
 }
 
+/**
+ * @brief Perform modular multiplication for 64-bit integers with a compile-time
+ *        modulus.
+ * @tparam Modulus The modulus.
+ * @tparam bit32 If true, won't use 128-bit arithmetic. You should ensure that
+ *         all inputs are small enough to avoid overflow (i.e. bit-32).
+ * @param a The first multiplicand.
+ * @param b The second multiplicand.
+ * @return (a * b) % Modulus
+ */
+template <uint64_t Modulus, bool bit32 = false>
+uint64_t modular_multiply_64(uint64_t a, uint64_t b) {
+  if constexpr (bit32)
+    return a * b % Modulus;
+  else
+    return static_cast<unsigned __int128>(a) * b % Modulus;
+}
+
 /**
  * @brief Perform modular exponentiation for 64-bit integers.
  * @tparam bit32 If true, won't use 128-bit arithmetic. You should ensure that
@@ -47,6 +65,6 @@ constexpr uint64_t fast_power_64(uint64_t base, uint64_t exponent, uint64_t modu
   }
   return result;
 }
-} // namespace weilycoder
+}
 
 #endif

weilycoder/number-theory/prime.hpp

@@ -6,7 +6,7 @@
  * @brief Prime Number Utilities
  */
 
-#include "modint.hpp"
+#include "mod_utility.hpp"
 #include <cstdint>
 #include <type_traits>
 
@@ -94,6 +94,12 @@ constexpr bool miller_rabin64(uint64_t n) {
  * @return true if n is prime, false if not prime.
  */
 constexpr bool miller_rabin32(uint32_t n) { return miller_rabin<true, 2, 7, 61>(n); }
+
+constexpr bool is_prime(uint64_t n) {
+  if (n <= UINT32_MAX)
+    return miller_rabin32(static_cast<uint32_t>(n));
+  return miller_rabin64(n);
+}
 } // namespace weilycoder
 
 #endif