104. Maximum Depth of Binary Tree (#72)

Author: Kohei Asai

solutions/maximumDepthOfBinaryTree.test.ts

@@ -0,0 +1,14 @@
+import { createBinaryTreeNode } from "../utilities/TreeNode";
+import maxDepth from "./maximumDepthOfBinaryTree";
+
+describe("104. Maximum Depth of Binary Tree", () => {
+  test("#1", () => {
+    expect(maxDepth(createBinaryTreeNode([3, 9, 20, null, null, 15, 7]))).toBe(
+      3
+    );
+  });
+
+  test("#2", () => {
+    expect(maxDepth(createBinaryTreeNode([]))).toBe(0);
+  });
+});

solutions/maximumDepthOfBinaryTree.ts

@@ -0,0 +1,9 @@
+import { TreeNode } from "../utilities/TreeNode";
+
+// 104. Maximum Depth of Binary Tree
+// https://leetcode.com/problems/maximum-depth-of-binary-tree/
+export default function maxDepth<T>(node: TreeNode<T> | null): number {
+  return node === null
+    ? 0
+    : Math.max(maxDepth(node.left), maxDepth(node.right)) + 1;
+}