Feat: 297. Serialize and Deserialize Binary Tree

Author: HC-kang

serialize-and-deserialize-binary-tree/HC-kang.ts

@@ -0,0 +1,51 @@
+class TreeNode {
+  val: number;
+  left: TreeNode | null;
+  right: TreeNode | null;
+  constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
+    this.val = val === undefined ? 0 : val;
+    this.left = left === undefined ? null : left;
+    this.right = right === undefined ? null : right;
+  }
+}
+
+/**
+ * https://leetcode.com/problems/serialize-and-deserialize-binary-tree
+ * T.C. O(n)
+ * S.C. O(n)
+ */
+function serialize(root: TreeNode | null): string {
+  return JSON.stringify(root);
+}
+
+function deserialize(data: string): TreeNode | null {
+  return JSON.parse(data);
+}
+
+/**
+ * Recursive
+ * T.C. O(n)
+ * S.C. O(n)
+ */
+function serialize(root: TreeNode | null): string {
+  return root
+    ? `${root.val},${serialize(root.left)},${serialize(root.right)}`
+    : 'null';
+}
+
+function deserialize(data: string): TreeNode | null {
+  const values = data.split(',');
+  let index = 0;
+
+  function dfs(): TreeNode | null {
+    const val = values[index++];
+    if (val === 'null') return null;
+
+    const node = new TreeNode(parseInt(val));
+    node.left = dfs();
+    node.right = dfs();
+    return node;
+  }
+
+  return dfs();
+}