diff --git a/cpp/2302/230221.cpp b/cpp/2302/230221.cpp
new file mode 100644
index 0000000..9811165
--- /dev/null
+++ b/cpp/2302/230221.cpp
@@ -0,0 +1,28 @@
+#include <vector>
+#include <iostream>
+
+/**
+ * 540. Single Element in a Sorted Array
+ *
+ * You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once.
+ * Return the single element that appears only once.
+ * Your solution must run in O(log n) time and O(1) space.
+ */
+
+class Solution {
+public:
+	static int singleNonDuplicate(const std::vector<int>& nums) {
+		int L = 0, R = nums.size() >> 1; // inclusive
+		while (L < R) {
+			int M = (L + R) >> 1;
+			if (nums[(M << 1) | 1] - nums[M << 1]) R = M;
+			else L = M + 1;
+		}
+		return nums[L << 1];
+	}
+};
+
+int main() {
+	std::cout << Solution::singleNonDuplicate({3,3,7,7,10,11,11});
+	return 0;
+}
diff --git a/cpp/2302/CMakeLists.txt b/cpp/2302/CMakeLists.txt
index 8a12700..68331da 100644
--- a/cpp/2302/CMakeLists.txt
+++ b/cpp/2302/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2302)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2302 230221-CN.cpp)
+ADD_EXECUTABLE(2302 230221.cpp)