Day i do not know

104. Maximum Depth of Binary Tree/Solution.cs

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+namespace _104._Maximum_Depth_of_Binary_Tree;
+
+public class Solution
+{
+    public int MaxDepth(TreeNode root)
+    {
+        var res = Recursion(0, root);
+        if (root != null)
+            res++;
+        return res;
+    }
+
+    private int Recursion(int count, TreeNode node)
+    {
+        if(node == null)
+            return 0;
+        var list = new List<int>();
+        if (node.left != null)
+            list.Add(Recursion(count + 1, node.left));
+        if (node.right != null)
+            list.Add(Recursion(count + 1, node.right));
+        if (list.Count > 0)
+            return list.Max();
+        return count;
+    }
+}