diff --git a/cpp/2304/230418-CN.cpp b/cpp/2304/230418-CN.cpp
new file mode 100644
index 0000000..0c1cd74
--- /dev/null
+++ b/cpp/2304/230418-CN.cpp
@@ -0,0 +1,39 @@
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+/**
+ * 1026. Maximum Difference Between Node and Ancestor
+ *
+ * Given the root of a binary tree, find the maximum value v for which there exist different nodes a and b where v = |a.val - b.val| and a is an ancestor of b.
+ * A node a is an ancestor of b if either: any child of a is equal to b or any child of a is an ancestor of b.
+ */
+
+class Solution {
+private:
+	static inline constexpr int MAX(int x, int y) { return x > y ? x : y; }
+	static inline constexpr int MIN(int x, int y) { return x < y ? x : y; }
+	static inline constexpr int ABS(int x) { return x < 0 ? -x : x; }
+
+	static int dfs(TreeNode*, int, int);
+public:
+	static int maxAncestorDiff(TreeNode*);
+};
+
+int Solution::maxAncestorDiff(TreeNode* r) {
+	return r ? dfs(r, r->val, r->val) : 0;
+}
+
+int Solution::dfs(TreeNode* n, int min, int max) {
+	int ret = MAX(ABS(n->val - min), ABS(n->val - max));
+	const int min_ = MIN(min, n->val), max_ = MAX(max, n->val);
+	if (n->left)
+		ret = MAX(ret, dfs(n->left, min_, max_));
+	if (n->right)
+		ret = MAX(ret, dfs(n->right, min_, max_));
+	return ret;
+}
diff --git a/cpp/2304/CMakeLists.txt b/cpp/2304/CMakeLists.txt
index b956bf7..aa1f5e7 100644
--- a/cpp/2304/CMakeLists.txt
+++ b/cpp/2304/CMakeLists.txt
@@ -4,4 +4,4 @@ PROJECT(2304)
 SET(CMAKE_CXX_STANDARD 23)
 SET(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-ADD_EXECUTABLE(2304 230418.cpp)
+ADD_EXECUTABLE(2304 230418-CN.cpp)