二叉树的序列化与反序列化

Leetcode题目链接

描述

详见中文题目链接。

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 {
private:
    void _serialize(TreeNode* root, ostringstream& out) {
        if (root) {
            out << root->val << ' ';
            _serialize(root->left, out);
            _serialize(root->right, out);
        } else {
            out << "# ";
        }
    }

    TreeNode* _deserialize(istringstream& in) {
        string val;
        in >> val;
        if (val == "#") return nullptr;
        TreeNode* root = new TreeNode(stoi(val));
        root->left = _deserialize(in);
        root->right = _deserialize(in);
        return root;
    }

public:

    // Encodes a tree to a single string.
    string serialize(TreeNode* root) {
        ostringstream out;
        _serialize(root, out);
        return out.str();
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string data) {
        istringstream in(data);
        return _deserialize(in);
    }
};

// Your Codec object will be instantiated and called as such:
// Codec ser, deser;
// TreeNode* ans = deser.deserialize(ser.serialize(root));