给定一个链表，要求每隔k个元素反转

给定一个链表，要求每隔k个元素反转，public void kReverse(Node node, int k)

即链表为1->2->3->4->5->6->7->8

当k=2时，链表为2->1->4->3->6->5->8->7

当k=5时，链表5->4->3->2->1->6->7->8

class Node<T> {
public  T data;
public  Node<T> next;

Node(T dataPortion) {
data = dataPortion;
next = null;

}

Node(T dataPortion, Node<T> nextNode) {
data = dataPortion;
next = nextNode;
}

}

public class ListKReverse {

public static void main(String[] args) {
ListKReverse s = new ListKReverse();

Node n1 = new Node(1);
Node n2 = new Node(2);
Node n3 = new Node(3);
Node n4 = new Node(4);
Node n5 = new Node(5);
Node n6 = new Node(6);
Node n7 = new Node(7);
Node n8 = new Node(8);

n1.next = n2;
n2.next = n3;
n3.next = n4;
n4.next = n5;
n5.next = n6;
n6.next = n7;
n7.next = n8;

Node head = s.ReverseInGroups(n1, 4);
while (head != null) {
System.out.print(head.data+"  ");
head = head.next;
}
System.out.println();
}

public Node ReverseInGroups(Node current, int k) {
if (current == null || current.next == null ) return current;
int n=0;
Node oldHead=current;
while(current!=null)
{
current=current.next;
n++;
}
System.out.println(n);
int reverseNum=n/k;
current=oldHead;
Node newHead = current;
Node previousGroupTail = null;
int count = 1;
int num=0;
while (current != null&&num<reverseNum) {
Node groupTail = current;
Node prev = null;
Node next = null;
for (int i = 1; i <= k && current != null; i++) {
next = current.next;
current.next = prev;
prev = current;
current = next;
}
if (count == 1) {
newHead = prev;
count++;
}
if (previousGroupTail != null) {
previousGroupTail.next = prev;
}
previousGroupTail = groupTail;
num++;
}
if(current!=null)
if (previousGroupTail != null)
previousGroupTail.next = current;

return newHead;
}
}