create: 0145-binary-tree-postorder-traversal.ts

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;
+}