add: 220307-CN [cpp]

cpp/2203/220307-CN.cpp

@@ -0,0 +1,23 @@
+#include <string>
+
+/**
+ * 504. Base 7
+ * Given an integer num, return a string of its base 7 representation.
+ */
+
+class Solution {
+public:
+	static std::string convertToBase7(int num) {
+		bool isNeg = num < 0;
+		std::string ret;
+		num = num < 0 ? -num : num;
+		while (num) {
+			ret.push_back('0' + num % 7);
+			num /= 7;
+		}
+		if (isNeg)
+			ret.push_back('-');
+		std::reverse(ret.begin(), ret.end());
+		return ret.empty() ? "0" : ret;
+	}
+};

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220306.cpp)
+ADD_EXECUTABLE(2203 220307-CN.cpp)