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 N1 aN1 N2 aN2 … NK aNK, where K is the number of nonzero terms in the polynomial, Ni and aNi (i=1, 2, …, K) are the exponents and coefficients, respectively. It is given that 1 <= K <= 10, 0 <= NK < … < N2 < N1 <=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
思路
用数组分别存储第一个多项式的指数和系数,读入第二个多项式时,每读一组指数、系数,就与第一个多项式各项做运算。
结果存储在map
里,以指数为key
,以系数为value
(value
默认初始值为0,直接累加即可)。若出现系数为0的项,则将其从map
中删除。
最后,map.size()
即是非0系数项个数,倒序遍历map
中的key
和value
即为按指数降序排列的结果(map
自动按key升序排列)。
注意:
- 结果要保留1位小数;
- 可能出现系数为0的情况(题目对系数的输入没有限制),需将其排除在外,否则测试点0无法通过。
代码
#include <iostream>
#include <iomanip>
#include<