diff --git a/cpp/2203/220329.cpp b/cpp/2203/220329.cpp
new file mode 100644
index 0000000..25eb92d
--- /dev/null
+++ b/cpp/2203/220329.cpp
@@ -0,0 +1,15 @@
+#include <vector>
+#include <bitset>
+
+class Solution {
+public:
+	static int findDuplicate(const std::vector<int>& nums) {
+		std::bitset<100008> s;
+		for (int i : nums) {
+			if (s[i])
+				return i;
+			s[i] = true;
+		}
+		return -1;
+	}
+};
diff --git a/cpp/2203/CMakeLists.txt b/cpp/2203/CMakeLists.txt
index baf4248..ba66ab5 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 220328.cpp)
+ADD_EXECUTABLE(2203 220329.cpp)