### ● 問題

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

### ● 思考點

求出節點左、右葉子值(最大值)，接著加一即求出。

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

求出節點左、右葉子值(最大值)，接著加一即求出。