add: 220602-CN [cpp]

cpp/2206/220602-CN.cpp

@@ -0,0 +1,60 @@
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+/**
+ * 450. Delete Node in a BST
+ * Given a root node reference of a BST and a key, delete the node with the given key in the BST. Return the root node reference (possibly updated) of the BST.
+ * Basically, the deletion can be divided into two stages:
+ * 1. Search for a node to remove.
+ * 2. If the node is found, delete the node.
+ */
+
+class Solution {
+private:
+	static TreeNode* mergeNode(TreeNode* L, TreeNode* R) {
+		if (!L || !R)
+			return (!L && !R) ? nullptr : (L ? L : R);
+		if (!L->right) {
+			L->right = R;
+			return L;
+		} else if (!R->left) {
+			R->left = L;
+			return R;
+		}
+		// Full
+		TreeNode* ptrP = R, * ptr = R->left;
+		while (ptr->left) {
+			ptrP = ptr;
+			ptr = ptr->left;
+		}
+		ptrP->left = ptr->right;
+		ptr->left = L;
+		ptr->right = R;
+		return ptr;
+	}
+
+public:
+	static TreeNode* deleteNode(TreeNode* root, int key) {
+		if (!root)
+			return nullptr;
+		if (root->val == key)
+			return mergeNode(root->left, root->right);
+		if (key < root->val)
+			root->left = deleteNode(root->left, key);
+		else // root->val < key
+			root->right = deleteNode(root->right, key);
+		return root;
+	}
+};
+
+int main() {
+	Solution::deleteNode(
+		new TreeNode(5, new TreeNode(3, new TreeNode(2), new TreeNode(4)), new TreeNode(6, nullptr, new TreeNode(7))),
+		3
+	);
+	return 0;
+}

cpp/2206/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2206)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2206 220602.cpp)
+ADD_EXECUTABLE(2206 220602-CN.cpp)