建立数组，数组下标作为指数

#include<iostream>
using namespace std;
const int maxn = 1e3 + 10;
double a[maxn], b[maxn];
int k;
void read(double a[])
{
    scanf("%d", &k);
    for (int i = 0; i < k; i++)
    {
        int exp;
        double coef;
        scanf("%d%lf", &exp, &coef);
        a[exp] = coef;
    }
}
int main()
{
    read(a);
    read(b);
    int cnt = 0;
    for (int i = 0; i < maxn; i++)
    {
        a[i] += b[i];
        if (a[i])cnt++;
    }
    printf("%d", cnt);
    for (int i = maxn; i >= 0; i--)
    {
        if (a[i])printf(" %d %.1f", i, a[i]);
    }
    return 0;
}