编程实现合并两个有序(假定为降序)单链表的函数，输入为两个有序链表的头结点，函数返回合并后新的链表的头节点，

要求：不能另外开辟新的内存存放合并的链表。

递归方式：

/*      * 递归方式     */    public LinkNode MergeLinkList(LinkNode head1,LinkNode head2){        if(head1 == null)            return head2;        if (head2 == null)            return head1;        LinkNode mergeHead = null;        if(head1.value < head2.value){            mergeHead = head1;            mergeHead.next = MergeLinkList(head1.next,head2);        }        else        {            mergeHead = head2;            mergeHead.next = MergeLinkList(head1,head2.next);        }        return mergeHead;    }

非递归方式：

/*     * 非递归方式     */    public LinkNode MergeLinkList_1(LinkNode head1,LinkNode head2){        if(head1 == null)            return head2;        if (head2 == null)            return head1;        LinkNode mergeHead;        LinkNode temp1 = null;        LinkNode temp2 = null;        if(head1.value < head2.value){            mergeHead = head1;            temp1 = head1.next;            temp2 = head2;        }else{            mergeHead = head2;            temp1 = head1;            temp2 = head2.next;        }        LinkNode temp = mergeHead;        while(temp1!=null || temp2 !=null){            if(temp1.value < temp2.value){                temp.next = temp1;                temp = temp1;                temp1 = temp1.next;            }else{                temp.next = temp1;                temp = temp2;                temp2 = temp2.next;            }        }        temp.next = temp1==null ? temp2:temp1;        return mergeHead;    }