104.MaximumDepthofBinaryTree_Kris.java

// Source : https://leetcode.com/problems/maximum-depth-of-binary-tree/
// Author : Kris
// Date : 2020-08-28

/***************************************************************************************************** 
 *
 * Given a binary tree, find its maximum depth.
 * 
 * The maximum depth is the number of nodes along the longest path from the root node down to the 
 * farthest leaf node.
 * 
 * Note: A leaf is a node with no children.
 * 
 * Example:
 * 
 * Given binary tree [3,9,20,null,null,15,7],
 * 
 * 3
 * / \
 * 9 20
 * / \
 * 15 7
 * 
 * return its depth = 3.
 ******************************************************************************************************/

/**
 * 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;
 * }
 * }
 */
classSolution {
publicintmaxDepth(TreeNoderoot) {
if (root == null) {
return0;
 }

intleft = maxDepth(root.left);
intright = maxDepth(root.right);

returnMath.max(left, right) + 1;
 }
}