(head)
Time Complexity: O(N^2)
    Space Complexity: O(1)
Time Complexity: O(N^2)
    Space Complexity: O(1)
Time Complexity : O ( N^2 ) Space Complexity : O ( 1 )
def removeDupsWithoutSet(head):
    """
    Time Complexity: O(N^2)
    Space Complexity: O(1)
    """
    current = head
    while current:
        runner = current
        while runner.next:
            if runner.next.val == current.val:
                runner.next = runner.next.next
            else:
                runner = runner.next
        current = current.next
def removeDupsWithoutSet ( head ) : current = head while current : runner = current while runner . next : if runner . next . val == current . val : runner . next = runner . next . next else : runner = runner . next current = current . next