设A与B分别为两个带有头结点的有序循环链表（所谓有序是指链接点按数据域值大小链接，本题不妨设按数据域值从小到大排列），list1和list2分别为指向两个链表的头指针。请写出将这两个链表合并为一个带头结点的有序循环链表的算法-Set A and B respectively with the first two nodes in an orderly cycle of chain (the so-called orderly means click the link data field val