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 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 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 Input2 1 2.4 0 3.2Sample Output
2 2 1.5 1 0.5
3 3 3.6 2 6.0 1 1.6
代码
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("\n");
55 }
56 return 0;
57 }
58 int comp(const Poly &x,const Poly &y)
59 {
60 return y.exp < x.exp;
61 }