diff --git a/cpp/2205/220531-CN.cpp b/cpp/2205/220531-CN.cpp
new file mode 100644
index 0000000..3a6ec00
--- /dev/null
+++ b/cpp/2205/220531-CN.cpp
@@ -0,0 +1,63 @@
+#include <vector>
+#include <string>
+#include <iostream>
+#include <functional>
+
+/**
+ * 269. Alien Dictionary
+ *
+ * Description is unavailable.
+ */
+
+class Solution {
+public:
+	static std::string alienOrder(const std::vector<std::string>& words) {
+		bool G[26][26]{{}}, present[26]{};
+		for (int i = 1; i < words.size(); ++i) {
+			const std::string& x = words[i - 1];
+			const std::string& y = words[i];
+			const int k = std::min(x.length(), y.length());
+			int j = 0;
+			for (; j < k; ++j) {
+				if (x[j] == y[j])
+					continue;
+				G[x[j] - 'a'][y[j] - 'a'] = true;
+				std::printf("%c > %c\n", x[j], y[j]);
+				break;
+			}
+			if (j == k && y.length() < x.length())
+				return "";
+		}
+		for (const auto& x : words)
+			for (const char c : x)
+				present[c - 'a'] = true;
+
+		char tp[26]{}, c[26]{};
+		int t = 26;
+		std::function<bool(int)> dfs = [&](int x) {
+			c[x] = -1;
+			for (int i = 0; i < 26; ++i) {
+				if (!present[i] || !G[x][i])
+					continue;
+				if (c[i] < 0 || (!c[i] && !dfs(i)))
+					return false;
+			}
+			c[x] = 1;
+			tp[--t] = x + 'a';
+			return true;
+		};
+
+		for (int i = 0; i < 26; ++i)
+			if (present[i] && !c[i] && !dfs(i))
+				return "";
+		for (int i = 0; i < 26; ++i)
+			if (present[i] && !c[i])
+				tp[--t] = i + 'a';
+		return {tp + t, tp + 26};
+	}
+};
+
+int main() {
+	std::cout << Solution::alienOrder({"ab", "adc"});
+	return 0;
+}
diff --git a/cpp/2205/CMakeLists.txt b/cpp/2205/CMakeLists.txt
index 8f5b42b..c3b55f1 100644
--- a/cpp/2205/CMakeLists.txt
+++ b/cpp/2205/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2205)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2205 220530.cpp)
+ADD_EXECUTABLE(2205 220531-CN.cpp)