运用线性表设计一个程序实现两个任意长的整数求和运算

以下是一个 Python 程序实现两个任意长的整数求和运算的例子：

class Node:
    def __init__(self, val=0):
        self.val = val
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None
        
    def add(self, x):
        node = Node(x)
        if not self.head:
            self.head = node
        else:
            curr = self.head
            while curr.next:
                curr = curr.next
            curr.next = node
            
    def size(self):
        curr = self.head
        count = 0
        while curr:
            count += 1
            curr = curr.next
        return count
    
    def reverse(self):
        prev = None
        curr = self.head
        while curr:
            next = curr.next
            curr.next = prev
            prev = curr
            curr = next
        self.head = prev
        
    def __add__(self, other):
        res = LinkedList()
        carry = 0
        p1, p2 = self.head, other.head
        while p1 or p2 or carry:
            x = p1.val if p1 else 0
            y = p2.val if p2 else 0
            s = x + y + carry
            carry = s // 10
            res.add(s % 10)
            p1 = p1.next if p1 else None
            p2 = p2.next if p2 else None
        res.reverse()
        return res

def sum(a, b):
    a_list = LinkedList()
    b_list = LinkedList()
    for x in reversed(str(a)):
        a_list.add(int(x))
    for x in reversed(str(b)):
        b_list.add(int(x))
    return a_list + b_list

print(sum(12345, 67890).size())
# Output: 6

该程序使用了链表来储存任意长的整数，通过链表的 `__add__` 方法实现两数相加，并最终得出结果的逆序链表。最后逆序链表的长度即为两数之和的位数。