feat: max depth

Author: soobing

maximum-depth-of-binary-tree/soobing3.ts

@@ -0,0 +1,16 @@
+
+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 maxDepth(root: TreeNode | null): number {
+  if(!root) return 0;
+  return 1 + Math.max(maxDepth(root.left), maxDepth(root.right))
+};