[LeetCode] 25.Reverse Nodes in k-Group[UNSOLVED]

　　This annoying problem do mind is perfect arrow.

　　After the head and tail here before can not be caused by the circular list next to the next copy of this form will be 

tailNode.next = headNode.next  # 4 next point to 2
tailprevNode.next = headNode  # 3 next point to 1(when k is large this node many hard to get)

　　

　　After the code is changed or failure: the cycle of death is not 1,6

 

    def reverseKGroup(self, head: ListNode, k: int) -> ListNode:
        # 0 1
        if head == None or head.next == None:
            return head
        # k == 0
        if k == 0 or k == 1:
            return head
        # swap node
        if k > 1:
            #0 node
            dummy = prevNode = ListNode(0)
            dummy.next = head
            #prepare node
            headNode = prevNode.next
            headnextNode = headNode.next
            tailNode = headNode
            tailprevNode = prevNode
            while tailNode != None:    #break when listnode end
                index = 1
                while index < k:            #break when find tailnode in k rule
                    tailNode = tailNode.next
                    tailprevNode = tailprevNode.next
                    index += 1
                #do swap (comment is k =4)
                prevNode.next = tailNode  # 0 next point to 4
                tailprevNode.next = headNode  # 3 next point to 1(when k is large this node many hard to get)
                headNode.next = tailNode.next  # 1 next point to 5
                tailNode.next = headnextNode  # 4 next point to 2



                #prepare for next
                # head = dummy.next
                prevNode = headNode
                tailprevNode = prevNode
                headNode = headNode.next
                if headNode != None:
                    headnextNode = headNode.next
                else:
                    break
                tailNode = headNode
            return head