diff --git a/cpp/2305/LC230509CN.cpp b/cpp/2305/LC230509CN.cpp
new file mode 100644
index 0000000..62f6aea
--- /dev/null
+++ b/cpp/2305/LC230509CN.cpp
@@ -0,0 +1,36 @@
+#include <string>
+
+/**
+ * 2437. Number of Valid Clock Times
+ *
+ * You are given a string of length 5 called time, representing the current time on a digital clock in the format "hh:mm". The earliest possible time is "00:00" and the latest possible time is "23:59".
+ * In the string time, the digits represented by the ? symbol are unknown, and must be replaced with a digit from 0 to 9.
+ * Return an integer answer, the number of valid clock times that can be created by replacing every ? with a digit from 0 to 9.
+ */
+
+class LC230509CN {
+public:
+	static int countTime(const std::string&) noexcept;
+};
+
+bool match(const char* s, const char* t) {
+	for (; *s && *t; ++s, ++t)
+		if (*s != *t && *t != '?')
+			return false;
+	return true;
+}
+
+int LC230509CN::countTime(const std::string& time) noexcept {
+	auto* time_ptr = time.c_str();
+	char buf[8];
+	int ret = 0;
+	for (int h = 0; h < 24; ++h) {
+		for (int m = 0; m < 60; ++m) {
+			std::sprintf(buf, "%02d:%02d", h, m);
+			ret += match(buf, time_ptr);
+		}
+	}
+	return ret;
+}
+
+using Solution = LC230509CN;
diff --git a/cpp/2305/defs.h b/cpp/2305/defs.h
index 65f75ad..3e048b2 100644
--- a/cpp/2305/defs.h
+++ b/cpp/2305/defs.h
@@ -75,6 +75,11 @@ public:
 	static std::vector<int> longestObstacleCourseAtEachPosition(const std::vector<int>&) noexcept;
 };
 
+class LC230507CN {
+public:
+	static int numPairsDivisibleBy60(const std::vector<int>&) noexcept;
+};
+
 class LC230508 {
 public:
 	static int diagonalSum(const std::vector<std::vector<int>>&) noexcept;
@@ -89,4 +94,9 @@ public:
 	static int minPushBox(const std::vector<std::vector<char>>&) noexcept;
 };
 
+class LC230509CN {
+public:
+	static int countTime(const std::string&) noexcept;
+};
+
 #endif //LEETCODE_CPP_DEFS_H