1002. A+B for Polynomials (25)

题目：

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

Input

Each input file contains one test case. Each case occupies 2 lines, and each line contains the information of a polynomial: K N1 a_N1 N2 a_N2 ... NK a_NK, where K is the number of nonzero terms in the polynomial, Ni and a_Ni (i=1, 2, ..., K) are the exponents and coefficients, respectively. It is given that 1 <= K <= 10，0 <= NK < ... < N2 < N1 <=1000.

Output

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

2 1 2.4 0 3.22 2 1.5 1 0.5

Sample Output

3 2 1.5 1 2.9 0 3.2

思路：

多项式加法，可以用vector也可以用数组。考虑到题目里的0 <= NK < ... < N2 < N1 <=1000. 使用数组更加方便。

此外还需要考虑到多项式加法后，一些像系数为0，不能输出和加完后直接为0的情况。

#include<iostream>#include<iomanip>using namespace std;int main(){double N[1001]={0.0};int num,max,i,k,f=0;double n;cin>>k;num=0; //多项式项数max=0; //最大项while(k>0){cin>>i>>n;if(N[i]==0){                   num++;   if(i>max)       max=i;}N[i]+=n;if(N[i]==0){                     --num;       //判断是否有相加后系数为0的情况发生}--k;if(k==0 && f==0)  //接收第二行{cin>>k;f++;}}cout<<num;if(num!=0)cout<<" ";elsecout<<endl;for(i=max;i>=0;i--){if(N[i]!=0.0){cout<<i<<" "<<setprecision(1)<<fixed<<N[i]; //精确到小数点后一位                        --num;if(num==0)cout<<endl;elsecout<<" ";}}system("pause");return 0;}