求二叉树的最大深度

package leetcode;

/*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.
*/

public class Maximum_depth_of_binary_tree {
    
     public static void main(String[] args) {
        
    }
     
     public int maxDepth(TreeNode root) {
         
         if( root == null ) {                 
             return 0;
         }else {
             return Math.max(maxDepth(root.left), maxDepth(root.right))+1;
         }
         
     }
     
}