已知一个单链表中的数据元素含有三类字符（即字母字符，数字字符和其它字符），试编写算法，构造三个循环链表，使每个循环链表中只含有同一类的字符，且利用原表中的结点空间作为这三个表的结点空间。-Known the data elements in a single linked list contains three types of characters (i.e., alphabetic characters, numeric characters and other characters), try to write algorithms to construct three circular linked list, so that each of the circular list contains only the characters of the same class, and use node in the original table space as the space of the junction of the three tables.