2022-5-11 每日一题-leetcode

题目链接：https://leetcode.cn/problems/serialize-and-deserialize-bst/

个人题解：前序遍历+递归

代码：

class Codec {
public:

    // Encodes a tree to a single string.
    string serialize(TreeNode* root) {
        string res;
        dfs_s(root,res);
        return res;
    }

    void dfs_s(TreeNode* root, string& res) {
        if(!root) return;

        res+=to_string(root->val)+' ';
        dfs_s(root->left,res);
        dfs_s(root->right,res);
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string str) {
        vector<int> data;
        stringstream ssin(str);
        int x, u = 0;
        while(ssin>>x) data.push_back(x);
        return dfs_d(data,u,INT_MIN,INT_MAX);
    }

    TreeNode* dfs_d(vector<int>& data, int& u, int minv, int maxv) {
        if (u == data.size() || data[u] < minv || data[u] > maxv) return NULL;
        auto root = new TreeNode(data[u ++ ]);
        root->left = dfs_d(data, u, minv, root->val);
        root->right = dfs_d(data, u, root->val + 1, maxv);
        return root;
    }
};

运行截图：