点击链接PAT甲级-AC全解汇总

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​​ <⋯​2​​ ​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:

2 1 2.4 0 3.2
2 2 1.5 1 0.5
1
2

Sample Output:

3 2 1.5 1 2.9 0 3.2
1

题意：
输入的是两个多项式
第一位是有几项，意味着后面有几对（指数，系数）
比如2 1 2.4 0 3.2的意思是这个多项式有2项，其中指数为1的系数是2.4，指数为0的系数是3.2
输出两个多项式的和，方式要和输入一样

我的代码：

#include
using namespace std;

int main()
{
    double exp[1010]={0};
    int K,cnt=0;
    cin>>K;
    for(int i=0;i<K;i++)
    {
        int index;
        double num;
        cin>>index>>num;
//        if(exp[index]==0)cnt++;
        exp[index]+=num;
    }
    cin>>K;
    for(int i=0;i<K;i++)
    {
        int index;
        double num;
        cin>>index>>num;
//        if(exp[index]==0)cnt++;
        exp[index]+=num;
    }
    for(int i=1000;i>=0;i--)
    {
        if(exp[i]!=0)cnt++;
    }

    cout<<cnt;
    for(int i=1000;i>=0;i--)
    {
        if(exp[i]!=0)printf(" %d %.1f",i,exp[i]);
    }
    return 0;
}

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注意： 可能有系数为0的时候，所以cnt要单独计算，不然一堆错误