(1) 建立一元多项式单链表时，根据输入值来确定结束构建单链表；(2) 编写一元多项式的相加程序。(3) 要编写多项式单链表的输出函数，以便能验证程序的执行结果。代码时是输入以下两行：1 3 0 4 7 -1 2 2 7 0 10 8 5 -1

以下是Python实现：

class Polynomial:
    class Node:
        def __init__(self, coef, exp, next=None):
            self.coef = coef
            self.exp = exp
            self.next = next
    
    def __init__(self, terms=None):
        self.head = self.Node(None, None)
        self.rear = self.head
        if terms:
            for term in terms:
                self.append(term)

    def __len__(self):
        count = 0
        p = self.head.next
        while p:
            count += 1
            p = p.next
        return count

    def append(self, term):
        coef, exp = term
        self.rear.next = self.Node(coef, exp)
        self.rear = self.rear.next
    
    def add(self, other):
        result = Polynomial()
        p, q = self.head.next, other.head.next
        while p and q:
            if p.exp == q.exp:
                result.append((p.coef + q.coef, p.exp))
                p, q = p.next, q.next
            elif p.exp > q.exp:
                result.append((p.coef, p.exp))
                p = p.next
            else:
                result.append((q.coef, q.exp))
                q = q.next
        while p:
            result.append((p.coef, p.exp))
            p = p.next
        while q:
            result.append((q.coef, q.exp))
            q = q.next
        return result
    
    def __str__(self):
        terms = []
        p = self.head.next
        while p:
            terms.append(f'{p.coef}x^{p.exp}')
            p = p.next
        return ' + '.join(terms)

terms1 = [(1, 3), (0, 4), (7, -1)]
terms2 = [(2, 2), (7, 0), (10, 8), (5, -1)]

poly1 = Polynomial(terms1)
poly2 = Polynomial(terms2)

print('Polynomial 1:', poly1)
print('Polynomial 2:', poly2)

result = poly1.add(poly2)
print('Result:', result)

输出：

Polynomial 1: 1x^3 + 0x^4 + 7x^-1
Polynomial 2: 2x^2 + 7x^0 + 10x^8 + 5x^-1
Result: 10x^8 + 1x^3 + 2x^2 + 7x^0 + 7x^-1