leetcode 104. maximum depth of binary tree

104. Maximum Depth of Binary Tree

Difficulty:: Easy

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],

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2
3
4
5
  3
/
9 20
/
15 7

return its depth = 3.

Solution

Language: Java

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* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class {
public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
if (root.left == null && root.right == null) {
return 1;
}
return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
}
}