01-Maximum-Depth-of-Binary-Tree.md

Maximum Depth of Binary Tree

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.

解法一：

传递level参数记录当前最大层数。题目给出的函数只有根节点参数，所以需要多写一个辅助函数。

funcmaxDepth(root*TreeNode) int { return_maxDepth(root, 0) } func_maxDepth(root*TreeNode, levelint) int { ifroot==nil { returnlevel } left:=_maxDepth(root.Left, level+1) right:=_maxDepth(root.Right, level+1) ifleft>right { returnleft } returnright }

解法二：

从叶子节点往回数。

funcmaxDepth(root*TreeNode) int { ifroot==nil { return0 } left:=maxDepth(root.Left) right:=maxDepth(root.Right) ifleft>right { returnleft+1 } returnright+1 }