PAT 1009

1009. Product of Polynomials (25)

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 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 Specification:

For each test case you should output the product 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 up to 1 decimal place.

Sample Input

2 1 2.4 0 3.2 
2 2 1.5 1 0.5 

Sample Output

3 3 3.6 2 6.0 1 1.6 
代码

 1 #include <stdio.h>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 
 6 typedef struct Poly{
 7     int exp;
 8     double coef;
 9 }Poly;
10 int comp(const Poly&,const Poly&);
11 int main()
12 {
13     int KA,KB;
14     Poly A[10],B[10],C[100];
15     int i,j;
16     while(scanf("%d",&KA) != EOF){
17         for(i=0;i<KA;++i){
18             scanf("%d%lf",&A[i].exp,&A[i].coef);
19         }
20         scanf("%d",&KB);
21         for(i=0;i<KB;++i){
22             scanf("%d%lf",&B[i].exp,&B[i].coef);
23         }
24         for(i=0;i<KA;++i)
25             for(j=0;j<KB;++j){
26                 C[i * KB + j].exp = A[i].exp + B[j].exp;
27                 C[i * KB + j].coef = A[i].coef * B[j].coef;
28             }
29         sort(C,C+KA*KB,comp);
30         double coef_sum = C[0].coef;
31         int exp = C[0].exp;
32         j = 0;
33         for(i=1;i<KA*KB;++i){
34             if(exp == C[i].exp){
35                 coef_sum += C[i].coef;
36             }
37             else{
38                 if (abs(coef_sum) > 0.000001){
39                     C[j].exp = exp;
40                     C[j++].coef = coef_sum;
41                 }
42                 exp = C[i].exp;
43                 coef_sum = C[i].coef;
44             }
45         }
46         if (abs(coef_sum) > 0.000001){
47             C[j].exp = exp;
48             C[j++].coef = coef_sum;
49         }
50         printf("%d",j);
51         for(i=0;i<j;++i){
52             printf(" %d %.1lf",C[i].exp,C[i].coef);
53         }
54         printf("
");
55     }
56     return 0;
57 }
58 int comp(const Poly &x,const Poly &y)
59 {
60     return y.exp < x.exp;
61 }