一人灼、問題描述
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.
Note: A leaf is a node with no children.
Example:
Given binary tree [3,9,20,null,null,15,7],
3
/
9 20
/
15 7
return its depth = 3.
二围段、解決思路
思路一：采用遞歸來解決精盅，二叉樹的高度等于左右子樹高度最大值 + 1
三垫卤、算法實現(xiàn)
public int maxDepth(TreeNode root) {
if(root == null) return 0;
int left = maxDepth(root.left);
int right = maxDepth(root.right);
return Math.max(left, right) + 1;
}
