(Note that in the examples below, all sequences are serializations of ListNode objects.)
Example 1:
Input: head = [1,2,-3,3,1]
Output: [3,1]
Note: The answer [1,2,1] would also be accepted.
Example 2:
Input: head = [1,2,3,-3,4]
Output: [1,2,4]
Example 3:
Input: head = [1,2,3,-3,-2]
Output: [1]
Constraints:
The given linked list will contain between 1 and 1000 nodes. Each node in the linked list has -1000 <= node.val <= 1000.