LeetCode-in-All
104. Maximum Depth of Binary Tree
Easy
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
Example 3:
Input: root = []
Output: 0
Example 4:
Input: root = [0]
Output: 1
Constraints:
- The number of nodes in the tree is in the range
[0, 104]. -100 <= Node.val <= 100
Solution
import com_github_leetcode.TreeNode
import kotlin.math.max
/*
* Example:
* var ti = TreeNode(5)
* var v = ti.`val`
* Definition for a binary tree node.
* class TreeNode(var `val`: Int) {
* var left: TreeNode? = null
* var right: TreeNode? = null
* }
*/
class Solution {
fun maxDepth(root: TreeNode?): Int {
return findDepth(root, 0)
}
private fun findDepth(node: TreeNode?, currentDepth: Int): Int {
var localCurrentDepth = currentDepth
if (node == null) {
return 0
}
localCurrentDepth++
return 1 + max(findDepth(node.left, localCurrentDepth), findDepth(node.right, localCurrentDepth))
}
}