1009 Product of Polynomials (25 分)

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 N​1​​ a​N​1​​​​ N​2​​ a​N​2​​​​ ... N​K​​ a​N​K​​​​

where K is the number of nonzero terms in the polynomial, N​i​​ and a​N​i​​​​ (i=1,2,⋯,K) are the exponents and coefficients, respectively. It is given that 1≤K≤10, 0≤N​K​​<⋯<N​2​​<N​1​​≤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

#include <iostream>
#include <cstdio>
#include <set>
#include <string>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <map>

using namespace std;

double a[1000005];

struct node{
	
	int n;
	double x;
};

int main(){
	
	int k1;
	cin>>k1;
	
	node b[k1];
	
	for(int i=0;i<k1;i++){
		
		cin>>b[i].n>>b[i].x;
	}
	
	int k2;
	cin>>k2;
	
	node c[k2];
	
	for(int i=0;i<k2;i++){
		
		cin>>c[i].n>>c[i].x;
	}
	
	for(int i=0;i<k1;i++){
		
		for(int j=0;j<k2;j++){
			
			int temp = b[i].n + c[j].n;
			double res = b[i].x * c[j].x;
			a[temp] += res;
		}
	}
	
	int cnt = 0;
	for(int i=1000004;i>=0;i--){
		
		if(a[i]!=0.0){
			
			cnt++;
		}
	}
	cout<<cnt;
	for(int i=1000004;i>=0;i--){
		
		if(a[i]!=0.0){
			
			printf(" %d %.1lf",i,a[i]);
		}
	}
	cout<<endl;
	
	return 0;
}