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程式語言 - LeetCode - C++ - 449. Serialize and Deserialize BST

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參考資訊：
https://www.cnblogs.com/grandyang/p/6224510.html

題目：


解答：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Codec {
public:

    // Encodes a tree to a single string.
    string serialize(TreeNode* root) {
        ostringstream os;

        auto dfs = [&](this auto&& dfs, TreeNode *n) {
            if (!n) {
                os << "# ";
                return;
            }

            os << n->val << " ";
            dfs(n->left);
            dfs(n->right);
        };

        dfs(root);
        return os.str();
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string data) {
        istringstream is(data);

        auto dfs = [&](this auto&& dfs) -> TreeNode* {
            string t = "";

            is >> t;
            if (t == "#") {
                return nullptr;
            }

            TreeNode *n = new TreeNode(stoi(t));
            n->left = dfs();
            n->right = dfs();
            return n;
        };

        return dfs();
    }
};

// Your Codec object will be instantiated and called as such:
// Codec* ser = new Codec();
// Codec* deser = new Codec();
// string tree = ser->serialize(root);
// TreeNode* ans = deser->deserialize(tree);
// return ans;