Create 297. 二叉树的序列化与反序列化.js

Author: yinxin630

297. 二叉树的序列化与反序列化.js

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+function TreeNode(val) {
+  this.val = val;
+  this.left = this.right = null;
+}
+
+/**
+ * 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) {
+  if (!root) {
+    return '';
+  }
+  const list = [root];
+  const result = [];
+  while (list.length > 0 && list.some((l) => l)) {
+    const node = list.shift();
+    result.push(node && node.val);
+    if (node) {
+      list.push(node.left);
+      list.push(node.right);
+    }
+  }
+  return result.map((x) => (typeof x === 'number' ? x : 'null')).join(',');
+};
+
+/**
+ * Decodes your encoded data to tree.
+ *
+ * @param {string} data
+ * @return {TreeNode}
+ */
+var deserialize = function (data) {
+  if (data.length === 0) {
+    return null;
+  }
+  const arr = data.split(',');
+  const root = new TreeNode(parseInt(arr[0]));
+  const list = [root];
+  let i = 1;
+  while (list.length > 0 && i < arr.length) {
+    const node = list.shift();
+    let nextVal = NaN;
+
+    nextVal = arr[i] === 'null' ? NaN : parseInt(arr[i]);
+    if (!isNaN(nextVal)) {
+      node.left = new TreeNode(nextVal);
+      list.push(node.left);
+    }
+    i++;
+    nextVal = arr[i] === 'null' ? NaN : parseInt(arr[i]);
+    if (!isNaN(nextVal)) {
+      node.right = new TreeNode(nextVal);
+      list.push(node.right);
+    }
+    i++;
+  }
+  return root;
+};
+
+/**
+ * Your functions will be called as such:
+ * deserialize(serialize(root));
+ */