diff --git a/cpp/2305/LC230509.cpp b/cpp/2305/LC230509.cpp
new file mode 100644
index 0000000..36d45d8
--- /dev/null
+++ b/cpp/2305/LC230509.cpp
@@ -0,0 +1,41 @@
+#include <vector>
+#include <bitset>
+
+/**
+ * 54. Spiral Matrix
+ *
+ * Given an m x n matrix, return all elements of the matrix in spiral order.
+ */
+
+class LC230509 {
+private:
+	static inline constexpr int dX[] = {0, 1, 0, -1};
+	static inline constexpr int dY[] = {1, 0, -1, 0};
+
+public:
+	static std::vector<int> spiralOrder(const std::vector<std::vector<int>>&) noexcept;
+};
+
+template<typename T>
+constexpr bool is_valid(T x, T y, T m, T n) {
+	return (x >= 0) && (x < m) && (y >= 0) && (y < n);
+}
+
+std::vector<int> LC230509::spiralOrder(const std::vector<std::vector<int>>& G) noexcept {
+	const int m = G.size(), n = G.front().size(), k = m * n;
+	std::vector<int> ret(k);
+	std::bitset<128> vis;
+	for (int pos = 0, x = 0, y = 0, d = 0;;) {
+		ret[pos] = G[x][y];
+		if (++pos >= k)
+			break;
+		vis[x * n + y] = true;
+		if (!is_valid(x + dX[d], y + dY[d], m, n) || vis[(x + dX[d]) * n + (y + dY[d])])
+			d = (d + 1) & 3;
+		x += dX[d];
+		y += dY[d];
+	}
+	return ret;
+}
+
+using Solution = LC230509;
diff --git a/cpp/2305/defs.h b/cpp/2305/defs.h
index 3e048b2..efbebe4 100644
--- a/cpp/2305/defs.h
+++ b/cpp/2305/defs.h
@@ -99,4 +99,13 @@ public:
 	static int countTime(const std::string&) noexcept;
 };
 
+class LC230509 {
+private:
+	static inline constexpr int dX[] = {0, 1, 0, -1};
+	static inline constexpr int dY[] = {1, 0, -1, 0};
+
+public:
+	static std::vector<int> spiralOrder(const std::vector<std::vector<int>>&) noexcept;
+};
+
 #endif //LEETCODE_CPP_DEFS_H
diff --git a/cpp/2305/main.cpp b/cpp/2305/main.cpp
index dec0240..a041976 100644
--- a/cpp/2305/main.cpp
+++ b/cpp/2305/main.cpp
@@ -12,13 +12,11 @@ std::ostream& operator<<(std::ostream& os, const std::vector<T>& x) noexcept {
 }
 
 int main() {
-	std::cout << LC230508CN::minPushBox(
-		{{'#','.','.','#','#','#','#','#'},
-		 {'#','.','.','T','#','.','.','#'},
-		 {'#','.','.','.','#','B','.','#'},
-		 {'#','.','.','.','.','.','.','#'},
-		 {'#','.','.','.','#','.','S','#'},
-		 {'#','.','.','#','#','#','#','#'}}
-	);
+	std::cout << LC230509::spiralOrder({
+		{2,3,4},
+		{5,6,7},
+		{8,9,10},
+		{11,12,13}
+	});
 	return 0;
 }