Problem Description: Maximum Depth of Binary Tree
Solution
The bottom-up approach will look like this:
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/**
* 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;
int left_depth = maxDepth(root.left);
int right_depth = maxDepth(root.right);
return Math.max(left_depth, right_depth) + 1;
}
}