@@ -0,0 +1,465 @@
+/**%0A * Definition for a binary tree node.%0A * public class TreeNode %7B%0A *     int val;%0A *     TreeNode left;%0A *     TreeNode right;%0A *     TreeNode(int x) %7B val = x; %7D%0A * %7D%0A */%0Aclass Solution %7B%0A    public int maxDepth(TreeNode root) %7B%0A        return dfs(root, 0);%0A    %7D%0A    public int dfs(TreeNode root, int level)%7B%0A        if (root != null) %7B%0A            return Math.max(dfs(root.left, level + 1), dfs(root.right, level + 1));%0A        %7D%0A        return level;%0A    %7D%0A%7D

solve problem 104