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.
给出一棵二叉树,求最大深度,最大深度是指根到最远的叶子的path长度
思路:
边界情况,root为null时深度为0
一般情况,取左子树和右子树深度较大的+1
上述步骤递归
public int maxDepth(TreeNode root) {
if(root == null) {
return 0;
}
int leftDep = maxDepth(root.left);
int rightDep = maxDepth(root.right);
return Math.max(leftDep, rightDep) + 1;
}