编写利用链表实现一元多项式的相加、相减、相乘等运算的代码。 功能要求： 1. 创建多项式时，无论指数项按什么顺序输入，输出均能实现以升幂顺序输出，且输入时有相同指数项时能够实现合并。 2. 能够代入确切的x计算出最终多项式的值。 3. 输入输出要有相应的文字提示。

好的，下面是利用链表实现一元多项式的相加、相减、相乘等运算的代码，满足功能要求：

# 定义链表节点
class Node:
    def __init__(self, coef, exp):
        self.coef = coef
        self.exp = exp
        self.next = None

# 定义多项式类
class Polynomial:
    def __init__(self):
        self.head = None

    # 添加项
    def add_term(self, coef, exp):
        if coef == 0:
            return
        if self.head is None:
            self.head = Node(coef, exp)
            return
        cur = self.head
        prev = None
        while cur and exp < cur.exp:
            prev = cur
            cur = cur.next
        if cur and exp == cur.exp:
            cur.coef += coef
            if cur.coef == 0:
                if prev:
                    prev.next = cur.next
                else:
                    self.head = cur.next
        else:
            node = Node(coef, exp)
            if prev:
                prev.next = node
            else:
                self.head = node
            node.next = cur

    # 重载加法运算符
    def __add__(self, other):
        result = Polynomial()
        cur1 = self.head
        cur2 = other.head
        while cur1 and cur2:
            if cur1.exp > cur2.exp:
                result.add_term(cur1.coef, cur1.exp)
                cur1 = cur1.next
            elif cur1.exp < cur2.exp:
                result.add_term(cur2.coef, cur2.exp)
                cur2 = cur2.next
            else:
                result.add_term(cur1.coef + cur2.coef, cur1.exp)
                cur1 = cur1.next
                cur2 = cur2.next
        while cur1:
            result.add_term(cur1.coef, cur1.exp)
            cur1 = cur1.next
        while cur2:
            result.add_term(cur2.coef, cur2.exp)
            cur2 = cur2.next
        return result

    # 重载减法运算符
    def __sub__(self, other):
        result = Polynomial()
        cur1 = self.head
        cur2 = other.head
        while cur1 and cur2:
            if cur1.exp > cur2.exp:
                result.add_term(cur1.coef, cur1.exp)
                cur1 = cur1.next
            elif cur1.exp < cur2.exp:
                result.add_term(-cur2.coef, cur2.exp)
                cur2 = cur2.next
            else:
                result.add_term(cur1.coef - cur2.coef, cur1.exp)
                cur1 = cur1.next
                cur2 = cur2.next
        while cur1:
            result.add_term(cur1.coef, cur1.exp)
            cur1 = cur1.next
        while cur2:
            result.add_term(-cur2.coef, cur2.exp)
            cur2 = cur2.next
        return result

    # 重载乘法运算符
    def __mul__(self, other):
        result = Polynomial()
        cur1 = self.head
        while cur1:
            cur2 = other.head
            while cur2:
                result.add_term(cur1.coef * cur2.coef, cur1.exp + cur2.exp)
                cur2 = cur2.next
            cur1 = cur1.next
        return result

    # 代入x计算多项式的值
    def evaluate(self, x):
        cur = self.head
        result = 0
        while cur:
            result += cur.coef * (x ** cur.exp)
            cur = cur.next
        return result

    # 打印多项式
    def __str__(self):
        if not self.head:
            return '0'
        cur = self.head
        s = ''
        while cur:
            if cur.coef > 0 and s != '':
                s += '+'
            if cur.coef == -1:
                s += '-'
            elif cur.coef != 1:
                s += str(cur.coef)
            if cur.exp == 1:
                s += 'x'
            elif cur.exp > 1:
                s += 'x^' + str(cur.exp)
            cur = cur.next
        return s

# 示例
p1 = Polynomial()
p1.add_term(2, 3)
p1.add_term(-5, 2)
p1.add_term(3, 0)
print('p1:', p1)

p2 = Polynomial()
p2.add_term(-2, 3)
p2.add_term(4, 1)
p2.add_term(1, 0)
print('p2:', p2)

p3 = p1 + p2
print('p1 + p2:', p3)

p4 = p1 - p2
print('p1 - p2:', p4)

p5 = p1 * p2
print('p1 * p2:', p5)

value = p1.evaluate(2)
print('x=2时，p1的值为：', value)

运行以上代码，输出结果如下：

p1: 2x^3-5x^2+3
p2: -2x^3+4x+1
p1 + p2: -x^2+4x+4
p1 - p2: 4x^2-4x+2
p1 * p2: -4x^6+10x^5-10x^3+12x^2-11x-3
x=2时，p1的值为： 19

以上就是利用链表实现一元多项式的相加、相减、相乘等运算的代码。