Write the code that will produce the given "after" result from the given "before" starting point by modifying links between the nodes shown and/or creating new nodes as needed. Assume that the nodes have already been declared and initialized to match the "before" figure below. There may be more than one way to write the code, but do NOT change any existing node's data field value. If a variable does not appear in the "after" picture, it doesn't matter what value it has after the changes are made. If a given node object does not appear in the "After" picture, you must free its memory to avoid a memory leak. Before list: 1 -> 2 -> 3 -> 4/ After list: 2 - 4 -> 3 -> 1/ Assume that you are using the following ListNode structure: struct ListNode { int data; ListNode next; // data stored in this node // a link to the next node in the list } // constructor ListNode(int data = 0, ListNode* next = nullptr) { };