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:
[0, 104].-100 <= Node.val <= 100/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int depth = 0;
int maxDepth(TreeNode* root, int d = 1) {
if (!(root))
return depth;
depth = max(depth, d);
if(root->left)
maxDepth(root->left, d+1);
if(root->right)
maxDepth(root->right, d+1);
return depth;
}
};/**
* 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) {
return solve(root, 0);
}
int solve(TreeNode node, int ht) {
if (node == null)
return ht;
return Math.max(solve(node.left, ht + 1), solve(node.right, ht + 1));
}
}