From 9bb1b6d4d15752e977a53d9b830edb65ffb7c9d5 Mon Sep 17 00:00:00 2001
From: M0nster92 <fahimalsafi@gmail.com>
Date: Sun, 18 Jun 2023 21:10:24 -0400
Subject: [PATCH] create: 0145-binary-tree-postorder-traversal.ts

---
 .../0145-binary-tree-postorder-traversal.ts   | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 typescript/0145-binary-tree-postorder-traversal.ts

diff --git a/typescript/0145-binary-tree-postorder-traversal.ts b/typescript/0145-binary-tree-postorder-traversal.ts
new file mode 100644
index 000000000..1cff52afe
--- /dev/null
+++ b/typescript/0145-binary-tree-postorder-traversal.ts
@@ -0,0 +1,30 @@
+/**
+ * Definition for a binary tree node.
+ * 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)
+ *     }
+ * }
+ */
+
+function postorderTraversal(root: TreeNode | null): number[] {
+    let res: number[] = [];
+
+    function dfs(root) {
+        if (!root) {
+            return;
+        }
+
+        dfs(root.left);
+        dfs(root.right);
+        res.push(root.val);
+    }
+
+    dfs(root);
+    return res;
+}