题目

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 sum 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 to 1 decimal place.

Sample Input:

1
2

2 1 2.4 0 3.2
2 2 1.5 1 0.5

Sample Output:

1

3 2 1.5 1 2.9 0 3.2

题解

思路

• 理解题意
• 题意是，给两个多项式让你相加
• 就是指数相同的要把系数相加
• 输入格式是，先给你项数，然后一个指数，一个系数，一个指数，一个系数……这样整两行
• 输出格式同样，指数按从大到小排列。
• 一开始想到用哈希表来做
• 但是因为结果要排序，怪麻烦的
• 算了，数组一把梭

代码

数据结构

• poly是一个数组
  • 下标代表指数
  • 值代表系数

算法

就20行代码，还有近一半是空行，我也不知道该怎么说算法了，一看代码就懂。

代码本体

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poly = [0 for _ in range(1001)]

def add():
    global poly
    line = input().split()[1:]
    i = 0
    while i < len(line) - 1:
        poly[int(line[i])] += float(line[i + 1])
        i += 2

add()
add()

count = 0
for i in range(1000,-1,-1):
    if poly[i] != 0:
        count += 1

print(count, end='')
for i in range(1000, -1, -1):
    if poly[i] != 0:
        print(" %d %.1f" % (i, poly[i]), end='')