Maximum Depth of Binary Tree solution

Author: kimjunyoung90

merge-two-sorted-lists/kimjunyoung90.java

@@ -15,11 +15,3 @@ public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
         }
     }
 }
-
-class ListNode {
-    int val;
-    ListNode next;
-    ListNode() {}
-    ListNode(int val) { this.val = val; }
-    ListNode(int val, ListNode next) { this.val = val; this.next = next; }
-}