1009 Product of Polynomials (Python实现)

This time, you are supposed to find A×B where A and B are two polynomials.

Input Specification:

Each input file contains one test case. Each case occupies 2 lines, and each line contains the information of a polynomial:

K N​1​​ a​N​1​​​​ N​2​​ a​N​2​​​​ ... N​K​​ a​N​K​​​​

where K is the number of nonzero terms in the polynomial, N​i​​ and a​N​i​​​​ (i=1,2,⋯,K) are the exponents and coefficients, respectively. It is given that 1≤K≤10, 0≤N​K​​<⋯<N​2​​<N​1​​≤1000.

Output Specification:

For each test case you should output the product of A and B in one line, with the same format as the input. Notice that there must be NO extra space at the end of each line. Please be accurate up to 1 decimal place.

Sample Input:

2 1 2.4 0 3.2
2 2 1.5 1 0.5

Sample Output:

3 3 3.6 2 6.0 1 1.6

Python实现：

dic1 = {}
dic2 = {}
dic = {}
x = input().split()
for j in range(1, len(x)):
    if j % 2 == 1:
        dic1[int(x[j])] = float(x[j + 1])
x = input().split()
for j in range(1, len(x)):
    if j % 2 == 1:
        dic2[int(x[j])] = float(x[j + 1])
dic1_keys = list(dic1.keys())
dic2_keys = list(dic2.keys())
for i in dic1_keys:
    for j in dic2_keys:
        try:
            dic[i+j] += dic1[i]*dic2[j]
        except KeyError:
            dic[i + j] = dic1[i] * dic2[j]
sorted_dic = sorted(dic.items(), key=lambda z: z[0], reverse=True)
list1 = []
for i in range(len(dic)):
    if sorted_dic[i][1] != 0:
        list1.append(str(sorted_dic[i][0]))
        list1.append(str(round(sorted_dic[i][1], 1)))
if len(list1) == 0:
    print("0")
else:
    print(int(len(list1) / 2), end=" ")
    print(" ".join(list1))
# 需要注意：
# 1.系数为0的情况需要过滤
# 2.结果为0时不能带空格