White Session - polynomial multiplication and addition operations -python language

Understand the meaning of problems

Title:
Design of two functions are required univariate polynomial and the product.

Input format:
input divider 2 rows, for each row number of the first polynomial given non-zero entries, then descending exponential manner enter a nonzero polynomial coefficient and the exponent (integer not exceeding the absolute value of both 1000). Between numbers separated by a space.

Output format:
output in 2 rows, respectively descending exponential manner, and outputs the product polynomial and polynomial coefficients and non-zero entries in the index. Between numbers separated by spaces, but the end can not have extra spaces. Zero polynomial should output 00.

Examples:
\ [\ text known two polynomials {:} \\ \ begin {align} & 3x ^ 4-5x ^ 2 + 6x-2 \\ & 5x ^ {20} -7x ^ 4 + 3x \ end { align} \]

# 输入样例：
4 3 4 -5 2  6 1  -2 0
3 5 20  -7 4  3 1

# 输出样例：
15 24 -25 22 30 21 -10 20 -21 8 35 6 -33 5 14 4 -15 3 18 2 -6 1
5 20 -4 4 -5 2 9 1 -2 0

Problem-solving ideas

Storage list may be used store and storage array, familiar to chaining, the linked list is stored. Wherein the pointer is defined format is as follows

Polynomial addition

def adds(l1, l2):  # l1,l2为链表,且不为空
    p1 = l1.head
    p2 = l2.head
    addRes = []
    while (p1 is not None) and (p2 is not None):  # 当p1和p2都部位空时，进行运算
        tmp1_exp = p1.get_data()[1]  # 获取p1指针处节点的指数
        tmp2_exp = p2.get_data()[1]  # 获取p2指针处节点的指数

        # 当指数相同时，系数相加，指数不变
        if tmp1_exp == tmp2_exp:
            addRes.append([p1.get_data()[0] + p2.get_data()[0], p1.get_data()[1]])
            p1 = p1.next  # 指针指向下一个节点
            p2 = p2.next

        # 当指数不相同时，选择较大的指数项存到结果中
        if tmp1_exp > tmp2_exp:
            addRes.append([p1.get_data()[0], p1.get_data()[1]])
            p1 = p1.next
        if tmp1_exp < tmp2_exp:
            addRes.append([p2.get_data()[0], p2.get_data()[1]])
            p2 = p2.next

    # 对于链表中剩余的节点添加到结果中
    while p1 is not None:
        addRes.append([p1.get_data()[0], p1.get_data()[1]])
        p1 = p1.next
    while p2 is not None:
        addRes.append([p2.get_data()[0], p2.get_data()[1]])
        p2 = p2.next

    # 此时的addRes结果
    # addRes [[5, 20], [-4, 4], [-5, 2], [9, 1], [-2, 0]]
    # 列表中每一项代表一各指数项，其中第一个元素代表系数，第二个元素代表指数。如[5，20]：5x^20

    # 以下是对addRes进行变形处理
    res1 = []
    for item in addRes:
        if item[0] != 0:  # 如果指数为0，即存在抵消情况，此时不应该输出
            res1.append(item[0])
            res1.append(item[1])
    if len(res1) == 0:  # 如果结果为0,需要输出：0  0
        return [0, 0]

    # 此时的输出结果变为
    # [5,20,-4,4,-5,2,9,1,-2,0]
    return res1

Polynomial multiplication

def muls(l1, l2):
    p1 = l1.head
    p2 = l2.head
    mulRes = []
    while p1 is not None:  # 将第一项的每一项乘以第二项的每一项
        tmp1 = p1.get_data()
        while p2 is not None:
            tmp2 = p2.get_data()
            # 将系数相乘和指数相加放入结果中
            mulRes.append([tmp1[0] * tmp2[0], tmp1[1] + tmp2[1]])
            p2 = p2.next
        p2 = l2.head  # 每次遍历完l2，都需要回到头指针，进行下一次遍历
        p1 = p1.next
    # 上述运算后，需要合并同类项。定义一个字典，key=指数，values=系数
    d = {}
    for item in mulRes:
        if item[1] not in d.keys():
            d[item[1]] = 0
        d[item[1]] += item[0]
    # 字典按照key的大小排序
    d = sorted(d.items(), key=lambda x: x[0], reverse=True)
    # 结果变形输出
    res2 = []
    for item in d:
        if item[1] != 0:
            res2.append(item[1])
            res2.append(item[0])
    if len(res2) == 0:
        return [0, 0]
    return res2

The complete code

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

    def get_data(self):
        return [self.coef, self.exp]


class List:
    def __init__(self, head):
        self.head = head

    # 添加节点
    def addNode(self, node):
        temp = self.head
        while temp.next is not None:
            temp = temp.next
        temp.next = node

        # 打印

    def printLink(self, head):
        res = []
        while head is not None:
            res.append(head.get_data())
            head = head.next
        return res


def adds(l1, l2):  # l1,l2为链表,且不为空
    p1 = l1.head
    p2 = l2.head
    addRes = []
    while (p1 is not None) and (p2 is not None):
        tmp1_exp = p1.get_data()[1]
        tmp2_exp = p2.get_data()[1]
        # 当指数相同时，系数相加
        if tmp1_exp == tmp2_exp:
            addRes.append([p1.get_data()[0] + p2.get_data()[0], p1.get_data()[1]])
            p1 = p1.next
            p2 = p2.next
        if tmp1_exp > tmp2_exp:
            addRes.append([p1.get_data()[0], p1.get_data()[1]])
            p1 = p1.next
        if tmp1_exp < tmp2_exp:
            addRes.append([p2.get_data()[0], p2.get_data()[1]])
            p2 = p2.next
    while p1 is not None:
        addRes.append([p1.get_data()[0], p1.get_data()[1]])
        p1 = p1.next
    while p2 is not None:
        addRes.append([p2.get_data()[0], p2.get_data()[1]])
        p2 = p2.next

    res1 = []
    for item in addRes:
        if item[0] != 0:
            res1.append(item[0])
            res1.append(item[1])
    if len(res1) == 0:
        return [0, 0]
    return res1


def muls(l1, l2):
    p1 = l1.head
    p2 = l2.head
    mulRes = []
    while p1 is not None:
        tmp1 = p1.get_data()
        while p2 is not None:
            tmp2 = p2.get_data()
            mulRes.append([tmp1[0] * tmp2[0], tmp1[1] + tmp2[1]])
            p2 = p2.next
        p2 = l2.head
        p1 = p1.next

    exps = []
    for item in mulRes:
        if item[1] not in exps:
            exps.append(item[1])

    d = {}
    for item in mulRes:
        if item[1] not in d.keys():
            d[item[1]] = 0
        d[item[1]] += item[0]

    d = sorted(d.items(), key=lambda x: x[0], reverse=True)

    res2 = []
    for item in d:
        # 如果多项式中出现抵消，即系数为0需要删除
        if item[1] != 0:
            res2.append(item[1])
            res2.append(item[0])
    # 如果最后出现空数组需要输出0 0
    if len(res2) == 0:
        return [0, 0]
    return res2


def print_list(x):
    for i in x[:-1]:
        print(i, end=' ')
    print(x[-1], end='')


# 输入
a1 = list(map(int, input().split()))
a2 = list(map(int, input().split()))

# 变为链表
if a1[0] != 0:
    head1 = Node(a1[1], a1[2])
    l1 = List(head1)
    if a1[0] > 1:
        for i in range(a1[0] - 1):
            node = Node(a1[i * 2 + 3], a1[i * 2 + 4])
            l1.addNode(node)

if a2[0] != 0:
    head2 = Node(a2[1], a2[2])
    l2 = List(head2)
    if a2[0] > 1:
        for i in range(a2[0] - 1):
            node = Node(a2[i * 2 + 3], a2[i * 2 + 4])
            l2.addNode(node)
# 考虑链表长度进行运算
if len(a1) == 1 and len(a2) == 1:  # 都为0，则输出都为0
    print_list([0, 0])
    print()
    print_list([0, 0])
elif len(a1) == 1 and len(a2) > 1:  # 一个为0，另一个为多项式
    print_list([0, 0])
    print()
    print_list(a2[1:])
elif len(a2) == 1 and len(a1) > 1:
    print_list([0, 0])
    print()
    print_list(a1[1:])
else:  # 都为多项式
    print_list(muls(l1, l2))
    print()
    print_list(adds(l1, l2))