Odd Even Linked List

328. Odd Even Linked List

Solution

1. Use two pointer to keep track of odd and even nodes.

2. Note to deal with head.next.next when head.next is None

   def oddEvenList(self, head):
    """
    :type head: ListNode
    :rtype: ListNode
    """
    dummy1 = odd = ListNode(0)
    dummy2 = even = ListNode(0)
    while head:
        odd.next = head
        even.next = head.next
        odd = odd.next
        even = even.next
        head = head.next.next if even else None
    odd.next = dummy2.next
    return dummy1.next