Leetcode #328. Odd Even Linked List
Given a singly linked list, group all odd nodes together followed by the even nodes. Please note here we are talking about the node number and not the value in the nodes.
The program should run in O(1) space complexity and O(nodes) time complexity.
Example:
Given 1->2->3->4->5->NULL, return 1->3->5->2->4->NULL.
1 class Solution(object): 2 def oddEvenList(self, head): 3 """ 4 :type head: ListNode 5 :rtype: ListNode 6 """ 7 if head == None or head.next == None: 8 return head 9 10 dummy = odd = head 11 connectNode = even = head.next 12 13 14 while even and odd: 15 t = even.next 16 if t == None: 17 break 18 19 odd.next = odd.next.next 20 # or odd.next = even.next 21 odd = odd.next 22 23 even.next = even.next.next 24 # or even.next = odd.next 25 even = even.next 26 27 odd.next = connectNode 28 29 return dummy 30
