diff --git a/cpp/2203/220316-CN.cpp b/cpp/2203/220316-CN.cpp
new file mode 100644
index 0000000..42b2ff6
--- /dev/null
+++ b/cpp/2203/220316-CN.cpp
@@ -0,0 +1,81 @@
+#include <string>
+#include <vector>
+#include <map>
+#include <unordered_map>
+#include <unordered_set>
+#include <iostream>
+
+class AllOne {
+private:
+	int n = 0;
+	std::unordered_map<int, std::string> id2Str;
+	std::unordered_map<std::string, int> str2Id;
+	std::map<int, std::unordered_set<int>> val2Id;
+	std::unordered_map<int, int> id2Val;
+public:
+	AllOne() = default;
+
+	void inc(const std::string& key) {
+		if (str2Id.count(key)) {
+			int idx = str2Id[key];
+			int& val = id2Val[idx];
+			if (val2Id[val].size() == 1) {
+				val2Id.erase(val);
+			} else {
+				val2Id[val].erase(idx);
+			}
+			val2Id[++val].insert(idx);
+		} else {
+			int x = str2Id[key] = ++n;
+			id2Str[x] = key;
+			id2Val[x] = 1;
+			val2Id[1].insert(x);
+		}
+	}
+
+	void dec(const std::string& key) {
+		int idx = str2Id[key];
+		int& val = id2Val[idx];
+		if (val == 1) {
+			id2Str.erase(idx);
+			if (val2Id[1].size() == 1)
+				val2Id.erase(1);
+			else
+				val2Id[1].erase(idx);
+			str2Id.erase(key);
+			id2Val.erase(idx);
+		} else {
+			if (val2Id[val].size() == 1) {
+				val2Id.erase(val);
+			} else {
+				val2Id[val].erase(idx);
+			}
+			val2Id[--val].insert(idx);
+		}
+	}
+
+	std::string getMaxKey() {
+		return str2Id.empty() ? "" : id2Str[*(val2Id.rbegin()->second.begin())];
+	}
+
+	std::string getMinKey() {
+		return str2Id.empty() ? "" : id2Str[*(val2Id.begin()->second.begin())];
+	}
+};
+
+int main() {
+	AllOne test;
+	test.inc("hello");
+	test.inc("hello");
+	std::cout << test.getMaxKey() << std::endl;
+	std::cout << test.getMinKey() << std::endl;
+	test.inc("123");
+	std::cout << test.getMaxKey() << std::endl;
+	std::cout << test.getMinKey() << std::endl;
+	test.dec("hello");
+	std::cout << test.getMaxKey() << std::endl;
+	std::cout << test.getMinKey() << std::endl;
+	test.dec("hello");
+	std::cout << test.getMaxKey() << std::endl;
+	std::cout << test.getMinKey() << std::endl;
+}
diff --git a/cpp/2203/CMakeLists.txt b/cpp/2203/CMakeLists.txt
index c5b6d19..30eaf5e 100644
--- a/cpp/2203/CMakeLists.txt
+++ b/cpp/2203/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220316.cpp)
+ADD_EXECUTABLE(2203 220316-CN.cpp)