add: 220319-CN [cpp]

cpp/2203/220319-CN.cpp

@@ -0,0 +1,31 @@
+#include <string>
+
+/**
+ * Definition for a binary tree node.
+ */
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+/**
+ * 606. Construct String from Binary Tree
+ * Given the root of a binary tree, construct a string consisting of parenthesis and integers from a binary tree with the preorder traversal way, and return it.
+ * Omit all the empty parenthesis pairs that do not affect the one-to-one mapping relationship between the string and the original binary tree.
+ */
+
+class Solution {
+public:
+	static std::string tree2str(TreeNode* root) {
+		if (!root)
+			return "";
+		auto ret = std::to_string(root->val);
+		if (root->left || root->right)
+			ret += "(" + tree2str(root->left) + ")";
+		if (root->right)
+			ret += "(" + tree2str(root->right) + ")";
+		return ret;
+	}
+};

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220318-CN.cpp)
+ADD_EXECUTABLE(2203 220319-CN.cpp)