Maximum Depth of Binary Tree

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.

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int maxDepth(TreeNode root) {
        return maxDep(root, 0);
    }
    
    public int maxDep(TreeNode node, int dep) {
        if (node == null) return dep;
        TreeNode rTree = node.left;
        TreeNode lTree = node.right;
        if (rTree == null && lTree == null) return dep+1;
        if (rTree == null)
            return maxDep(lTree, dep+1);
        if (lTree == null)
            return maxDep(rTree, dep+1);
        int ldep = maxDep(lTree, dep+1);
        int rdep = maxDep(rTree, dep+1);
        return (ldep > rdep) ? ldep : rdep;
        
    }
}