单链表每k个节点为一组进行反转（最后不满k个时不反转）

public class LinkReverse2 {

    public static Node mhead=null;
    public static Node mtail=null;

    public static Node newLink(int n){
        Node head = new Node();
        head.setData(1);
        head.setNext(null);
        Node tmp = head;
        for(int i=2;i<=n;i++){
            Node newNode = new Node();
            newNode.setData(i);
            newNode.setNext(null);
            tmp.setNext(newNode);
            tmp = newNode;
        }
        return head;
    }

    public static void main(String[] args) {
        Node node = newLink(10);
        pritNode(node);
//        Node node1 = reverseKLink(node,3);
//        Node node1 = reverse(node,2);
        Node node1 = reverseLink3(node,4);
        pritNode(node1);

    }
    public static void pritNode(Node head){
        Node temp = head;
        while(temp !=null){
            System.out.print(temp.getData()+"->");
            temp = temp.getNext();
        }
        System.out.println();
    }

    /*public static Node reverseLink(Node head){
        Node pre=null,cur=head,next=null;
        while(cur!=null){
            next=cur.getNext();
            cur.setNext(pre);
            pre=cur;
            cur=next;
        }
        return pre;
    }*/

    /*public static Node reverseKLink(Node head,int k){
        Node pre=null,cur=head,next=null;

        Node pnext=null,global_head=null;
        int i=0;
        Node tmp=null;

        while(cur!=null){
            next = cur.getNext();

            if(tmp==null) tmp=cur;   //tmp记录当前组反转完最后一个节点
            if(pnext!=null) pnext.setNext(cur);  //pnext是上一组反转完最后一个节点

            cur.setNext(pre);
            pre=cur;
            cur = next;

            i++;
            if(i>=k){  //当前组反转完成的时候
                if(global_head==null){
                    global_head=pre;
                }
                if(pnext!=null){  //将上一组反转完的最后一个节点指向 当前组反转完后的第一个节点
                    pnext.setNext(pre);
                }
                pnext=tmp; //迭代

                i=0;  //新的一组反转时 关键数据初始化
                tmp=null;
                pre=null;
            }
        }
        return global_head;
    }*/

    //反转每组
    public static void inreverse(Node left,Node right){
        Node pre=null,cur=left,next=null;
        while(pre!=right){
            next = cur.getNext();
            cur.setNext(pre);
            pre=cur;
            cur=next;
        }
        if(mtail!=null) mtail.setNext(right);
        mhead=right;
        mtail=left;
    }
    //每k个节点为一组反转
    public static Node reverseLink3(Node head,int k){
        Node cur=head,global_head=head;
        int i=1;
        Node left=null,right=null;
        while(cur!=null){
            if(i%k==1)
                left=cur;
            right=cur;
            cur=cur.getNext();
            if(i%k==0){
                inreverse(left,right);
                if(mtail!=null){
                    mtail.setNext(cur);
                }
                if(global_head==head){
                    global_head = mhead;
                }
            }

            i++;
        }
        return global_head;
    }

}