[LeetCode] 104. Maximum Depth of Binary Tree
ProblemPermalink
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, 10^4].
- -100 <= Node.val <= 100
SolutionPermalink
LogicPermalink
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노드의 왼쪽 혹은 오른쪽 자식 노드가 있으면 깊이를 1추가한다.
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Root노드부터 1번 과정을 수행하여 전체 이진트리를 탐색하며 최고 깊이를 찾아낸다.
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왼쪽과 오른쪽 자식 노드 모두 존재하지 않으면 탐색을 종료하고 최고 깊이를 반환한다.
CodePermalink
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val = val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val = val; * this.left = left; * this.right = right; * } * } */ class Solution { public int maxDepth(TreeNode root) { if (root == null) return 0; return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1; } }
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