我要考甲级！！！
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 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
Sample Output:
3 2 1.5 1 2.9 0 3.2
代码：（注意一点就是输出非零项！！）
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
struct node
{
int index;
double data;
} a[1005],b[1005],c[2005];
int f[1005];///标记数组。
bool compare(node a,node b)
{
return a.index>b.index;
}
int main()
{
int n,m;
scanf("%d",&n);
for(int i=0; i<n; i++)
{
scanf("%d %lf",&a[i].index,&a[i].data);
}
scanf("%d",&m);
int k = 0;
for(int i=0; i<m; i++)
{
scanf("%d %lf",&b[i].index,&b[i].data);
int j;
for(j=0; j<n; j++)
{
if(b[i].index==a[j].index)
{
f[j] = 1;
if(a[j].data + b[i].data > 0)///这里的>可以换成！=，只能说这个题目数据有点水。
{
c[k].data = a[j].data + b[i].data;
c[k++].index = a[j].index;
}
break;///跳出的话表示找到了。
}
}
if(j==n)///没有跳出，表示没有a[],和b[]没有重复的元素。
{
c[k++] = b[i];
}
}
for(int i=0; i<n; i++)
{
if(f[i]==0)
{
c[k++] = a[i];
}
}
sort(c,c+k,compare);///用sort函数排序。
if(k==0)///这里需要注意，0的时候单独输出。
{
printf("0\n");
return 0;
}
printf("%d ",k);
for(int i=0; i<k; i++)
{
printf(i==k-1?"%d %.1lf\n":"%d %.1lf ",c[i].index,c[i].data);
}
return 0;
}