leetcode 104) Maximum Depth of Binary Tree

LV. Easy 😎

https://leetcode.com/problems/maximum-depth-of-binary-tree/

Maximum Depth of Binary Tree - LeetCode

 

문제

Given the root of a binary tree, return its maximum depth.

A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

 

Example 1:

Input: root = [3,9,20,null,null,15,7]
Output: 3

Example 2:

Input: root = [1,null,2]
Output: 2

 

Constraints:

• The number of nodes in the tree is in the range [0, 104].
• -100 <= Node.val <= 100

 

문제 해결법

오른쪽 왼쪽으로 갈 때마다 깊이를 +1 해주고 ans과 비교해서 max 값을 저장해주면 끝!

 

해결 코드

class Solution {
private:
	int ans;
	void node(TreeNode* root, int deep) {
		ans = max(ans, deep);
		if (!root)
			return ;
		else {
			node(root->left, deep + 1);
			node(root->right, deep + 1);
		}
	}
public:
	int maxDepth(TreeNode* root) {
		ans = 0;
		node(root, 0);
		return ans;
	}
};