[LeetCode] 104. Maximum Depth of Binary Tree (Easy) (JAVA)
Title address: https://leetcode.com/problems/maximum-depth-of-binary-tree/
Title description:
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.
Topic
Given a binary tree, find its maximum depth.
The depth of the binary tree is the number of nodes on the longest path from the root node to the farthest leaf node.
Explanation: A leaf node refers to a node without child nodes.
Problem solving method
Relatively simple, directly use recursion, which is the deeper one of the left and right subtrees
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public int maxDepth(TreeNode root) {
if (root == null) return 0;
return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
}
}
Execution time: 0 ms, beat 100.00% of users
in all Java submissions Memory consumption: 39.8 MB, beat 5.75% of users in all Java submissions