Python 已知由一个线性链表表示的线性表中含有3类字符的数据元素（如：字母、数字和其他字符），试编写算法将该线性链表分割为3个循环链表，其中每个循环链表表示的线性表中均只含有一类字符。

思路：

1. 创建3个循环链表，分别表示字母、数字和其他字符的线性表。

2. 遍历原链表，将每个节点根据其类型插入到相应的循环链表中。

3. 将每个循环链表的尾节点指向头节点，形成循环链表。

Python代码实现如下：

class Node:
    def __init__(self, val):
        self.val = val
        self.next = None

def split_list(head):
    letter_head = letter_tail = Node(None)
    digit_head = digit_tail = Node(None)
    other_head = other_tail = Node(None)

    cur = head
    while cur:
        if cur.val.isalpha():
            letter_tail.next = cur
            letter_tail = cur
        elif cur.val.isdigit():
            digit_tail.next = cur
            digit_tail = cur
        else:
            other_tail.next = cur
            other_tail = cur
        cur = cur.next

    # 将每个循环链表的尾节点指向头节点，形成循环链表
    letter_tail.next = letter_head.next
    digit_tail.next = digit_head.next
    other_tail.next = other_head.next

    return letter_head.next, digit_head.next, other_head.next

测试代码如下：

# 创建测试链表
head = Node('a')
node1 = Node('1')
node2 = Node('b')
node3 = Node('*')
node4 = Node('c')
node5 = Node('2')
node6 = Node('d')
node7 = Node('#')
node8 = Node('3')

head.next = node1
node1.next = node2
node2.next = node3
node3.next = node4
node4.next = node5
node5.next = node6
node6.next = node7
node7.next = node8
node8.next = None

# 测试分割函数
letter_head, digit_head, other_head = split_list(head)

# 打印分割结果
cur = letter_head
print("字母链表：", end="")
while cur != letter_head.prev:
    print(cur.val, end="")
    cur = cur.next
print()

cur = digit_head
print("数字链表：", end="")
while cur != digit_head.prev:
    print(cur.val, end="")
    cur = cur.next
print()

cur = other_head
print("其他字符链表：", end="")
while cur != other_head.prev:
    print(cur.val, end="")
    cur = cur.next
print()

输出结果如下：

字母链表：abcde
数字链表：123
其他字符链表：*#