题解 | #链表的奇偶重排#

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
#
# @param head ListNode类
# @return ListNode类
#
class Solution:
    def oddEvenList(self, head: ListNode) -> ListNode:
        # write code here
        cur1 = dummy1 = ListNode(0)
        cur2 = dummy2 = ListNode(0)
        flag = True
        while head:
            if flag:
                cur1.next = head
                cur1 = cur1.next
            else:
                cur2.next = head
                cur2 = cur2.next
            flag = not flag
            head = head.next
        # join the first listnodes end with the second start
        cur1.next = dummy2.next
        # must assign the end of cur2 to None, else it will become a ring
        cur2.next = None
        return dummy1.next