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Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment.
Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.
For example, you may serialize the following tree
1
/ 2 3
/ 4 5
as "[1,2,3,null,null,4,5]", just the same as how LeetCode OJ serializes a binary tree. You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.
Note: Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms should be stateless.
https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
串行化和反串行化树。
串行化，中序遍历树，如果left或者right没有孩子，就用N代替，用#连接各个节点。
比图题中的例子，串行化之后是1#2#N#N#3#4#N#N#5#N#N。
反串行化还是中序遍历，递归建出树。
LDR方法有2个返回值，node是当前的节点对象，i是nodes下标。
1 /** 2 * Definition for a binary tree node. 3 * function TreeNode(val) { 4 * this.val = val; 5 * this.left = this.right = null; 6 * } 7 */ 8 /** 9 * Encodes a tree to a single string. 10 * 11 * @param {TreeNode} root 12 * @return {string} 13 */ 14 var serialize = function(root) { 15 var res = ""; 16 LDR(root); 17 if(res[0] === ‘#‘){ 18 res = res.substring(1); 19 } 20 return res; 21 22 function LDR(node){ 23 if(node !== null && node.val !== undefined){ 24 res += "#" + node.val; 25 if(node.left !== null){ 26 LDR(node.left); 27 }else{ 28 res += "#N"; 29 } 30 if(node.right !== null){ 31 LDR(node.right); 32 }else{ 33 res += "#N"; 34 } 35 } 36 } 37 }; 38 39 /** 40 * Decodes your encoded data to tree. 41 * 42 * @param {string} data 43 * @return {TreeNode} 44 */ 45 var deserialize = function(data) { 46 var nodes = data.split(‘#‘); 47 return LDR(0).node; 48 49 function LDR(i){ 50 if(nodes[i] !== undefined && nodes[i] !== "" && nodes[i] !== ‘N‘){ 51 var root = new TreeNode(parseInt(nodes[i])); 52 i++; 53 var res = LDR(i); 54 i = res.i; 55 root.left = res.node; 56 res = LDR(i); 57 i = res.i; 58 root.right = res.node; 59 return {node : root, i : i}; 60 }else{ 61 return {node : null, i : ++i}; 62 } 63 } 64 };
[LeetCode][JavaScript]Serialize and Deserialize Binary Tree
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原文地址：http://www.cnblogs.com/Liok3187/p/4925945.html
