题目链接：http://www.patest.cn/contests/pat-a-practise/1002

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.

2 1 2.4 0 3.2
2 2 1.5 1 0.5

3 2 1.5 1 2.9 0 3.2

代码如下：

#include <cstdio>
#include <cstring>
double a[1017];
int main()
{
    int k, k1, k2, k3;
    while(~scanf("%d",&k1))
    {
        memset(a,0,sizeof(a));
        int x;
        double y;
        int maxx = 0;
        for(int i = 0; i < k1; i++)
        {
            scanf("%d%lf",&x,&y);
            a[x]+=y;
            if(x > maxx)
                maxx = x;
        }
        scanf("%d",&k2);
        for(int i = 0; i < k2; i++)
        {
            scanf("%d%lf",&x,&y);
            a[x]+=y;
            if(x > maxx)
                maxx = x;
        }
        k = 0;
        for(int i = 0; i <= maxx; i++)
        {
            if(a[i]!=0)
                k++;
        }
        printf("%d",k);
        for(int i = maxx; i >= 0; i--)
        {
            if(a[i] != 0)
                printf(" %d %.1lf",i,a[i]);
        }
        printf("\n");
    }
    return 0;
}

1002. A+B for Polynomials (25) （数学啊 ZJU_PAT）