序列化二叉树

剑指 Offer 37. 序列化二叉树

请实现两个函数，分别用来序列化和反序列化二叉树。

你需要设计一个算法来实现二叉树的序列化与反序列化。这里不限定你的序列 / 反序列化算法执行逻辑，你只需要保证一个二叉树可以被序列化为一个字符串并且将这个字符串反序列化为原始的树结构。

提示：输入输出格式与 LeetCode 目前使用的方式一致，详情请参阅 LeetCode 序列化二叉树的格式。你并非必须采取这种方式，你也可以采用其他的方法解决这个问题。

示例：

输入：root = [1,2,3,null,null,4,5]
输出：[1,2,3,null,null,4,5]

注意：本题与主站 297 题相同：https://leetcode.cn/problems/serialize-and-deserialize-binary-tree/

原站题解

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上次编辑到这里，代码来自缓存点击恢复默认模板

/** * 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) { } // Decodes your encoded data to tree. TreeNode* deserialize(string data) { } }; // Your Codec object will be instantiated and called as such: // Codec codec; // codec.deserialize(codec.serialize(root));

javascript 解法, 执行用时: 112 ms, 内存消耗: 54.2 MB, 提交时间: 2022-11-23 17:17:55

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */

var serialize = function(root) {
    if (root == null) {
        return "X";
    }
    const left = "(" + serialize(root.left) + ")";
    const right = "(" + serialize(root.right) + ")";
    return left + root.val + right;
};

var deserialize = function(data) {
    const ptr = [0];
    return parse(data, ptr);
};

const parse = (data, ptr) => {
    if (data[ptr[0]] === 'X') {
        ++ptr[0];
        return null;
    }
    let cur = new TreeNode(0);
    cur.left = parseSubtree(data, ptr);
    cur.val = parseInt(data, ptr);
    cur.right = parseSubtree(data, ptr);
    return cur;
}

const parseSubtree = (data, ptr) => {
    ++ptr[0]; // 跳过左括号
    const subtree = parse(data, ptr);
    ++ptr[0]; // 跳过右括号
    return subtree;
}

const parseInt = (data, ptr) => {
    let x = 0, sgn = 1;
    if (isNaN(Number(data[ptr[0]]))) {
        sgn = -1;
        ++ptr[0];
    }
    while (!isNaN(Number(data[ptr[0]]))) {
        x = x * 10 + data[ptr[0]++].charCodeAt() - '0'.charCodeAt();
    }
    return x * sgn;
}

/**
 * Your functions will be called as such:
 * deserialize(serialize(root));
 */

javascript 解法, 执行用时: 896 ms, 内存消耗: 51.5 MB, 提交时间: 2022-11-23 17:17:20

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */

/**
 * Encodes a tree to a single string.
 *
 * @param {TreeNode} root
 * @return {string}
 */
var serialize = function(root) {
    return rserialize(root, '');
};

/**
 * Decodes your encoded data to tree.
 *
 * @param {string} data
 * @return {TreeNode}
 */
var deserialize = function(data) {
    const dataArray = data.split(",");
    return rdeserialize(dataArray);
};

const rserialize = (root, str) => {
    if (root === null) {
        str += "None,";
    } else {
        str += root.val + '' + ",";
        str = rserialize(root.left, str);
        str = rserialize(root.right, str);
    }
    return str;
}

const rdeserialize = (dataList) => {
    if (dataList[0] === "None") {
        dataList.shift();
        return null;
    }

    const root = new TreeNode(parseInt(dataList[0]));
    dataList.shift();
    root.left = rdeserialize(dataList);
    root.right = rdeserialize(dataList);

    return root;
}

/**
 * Your functions will be called as such:
 * deserialize(serialize(root));
 */

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