已知一个双向链表，从第二个元素开始已经呈递增有序，随意 输入几个数字，把第一个数字插进去，条件的是呈递增有序-Known to a two-way list, from the beginning of the second element has been increasing in an orderly manner, free importation of a few figures into the first number, and the conditions that wer