add: 230405-CN

cpp/2304/230405-CN.cpp

@@ -0,0 +1,25 @@
+#include <iostream>
+#include <numeric>
+
+/**
+ * 2427. Number of Common Factors
+ *
+ * Given two positive integers a and b, return the number of common factors of a and b.
+ * An integer x is a common factor of a and b if x divides both a and b.
+ */
+
+class Solution {
+public:
+	static constexpr inline int commonFactors(int a, int b) {
+		int x = std::gcd(a, b), ret = 0;
+		for (int i = 1; i * i <= x; ++i)
+			ret += ((x % i == 0) << 1) - (i * i == x);
+		return ret;
+	}
+};
+
+int main() {
+	std::cout << Solution::commonFactors(452, 392);
+	std::cout << std::gcd(452, 392);
+	return 0;
+}

cpp/2304/CMakeLists.txt

@@ -4,4 +4,4 @@ PROJECT(2304)
 SET(CMAKE_CXX_STANDARD 23)
 SET(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-ADD_EXECUTABLE(2304 230404.cpp)
+ADD_EXECUTABLE(2304 230405-CN.cpp)