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 3.22 2 1.5 1 0.5

Sample Output

3 3 3.6 2 6.0 1 1.6

#include <iostream>#include <vector>#include <map>using namespace std;struct Node{  int exp;  double coef;};vector<Node> arra;vector<Node> arrb;map<int, double> ans;int main(int argc, char* argv[]){  int i,j,k;  Node node;  arra.empty();  arrb.empty();  map<int, double>::iterator it;  scanf("%d", &k);  for(i = 0; i < k; ++i)  {    scanf("%d%lf",&node.exp, &node.coef);    arra.push_back(node);  }  scanf("%d", &k);  for(i = 0; i < k; ++i)  {    scanf("%d%lf",&node.exp, &node.coef);    arrb.push_back(node);  }  for(i = 0; i < arra.size(); i++){    for(j = 0;j < arrb.size(); ++j){      it = ans.find(arra[i].exp + arrb[j].exp);      if(it != ans.end()){        it->second += arra[i].coef * arrb[j].coef;      } else{        ans[arra[i].exp+arrb[j].exp] = arra[i].coef * arrb[j].coef;      }    }  }  map<int, double>::reverse_iterator rit;  i = 0;  for(rit = ans.rbegin(); rit != ans.rend(); rit++){    if(rit->second == 0.0)      i++;  }  printf("%d",ans.size()-i);  for(rit = ans.rbegin(); rit != ans.rend(); rit++){    if(rit->second != 0.0)      printf(" %d %.1lf",rit->first,rit->second);  }  printf("\n");  return 0;}