1009. Product of Polynomials (25)

#include "stdafx.h"
#include <iostream>
#include <map>

using namespace std;

int main()
{
	int n1;
	scanf("%d", &n1);

	int i, a;
	double b;
	map<int, double> m[2];

	for(i = 1; i <= n1; i++)
	{
		scanf("%d%lf", &a, &b);
		m[0][a] = b;
	}

	int n2;
	scanf("%d", &n2);

	map<int, double> ::reverse_iterator it;
	int first;
	double second;

	for(i = 1; i <= n2; i++)
	{
		scanf("%d%lf", &a, &b);

		for(it = m[0].rbegin(); it != m[0].rend(); it++)
		{
			first = it->first + a;
			second = it->second * b;
			m[1][first] += second;
		}
	}

	int count = 0;
	for(it = m[1].rbegin(); it != m[1].rend(); it++)
	{
		second = it->second;
		if(second != 0)
		{
			count++;
		}
	}

	printf("%d", count);

	for(it = m[1].rbegin(); it != m[1].rend(); it++)
	{
		first = it->first;
		second = it->second;

		if(second != 0)
		{
			printf(" %d %.1lf", first, second);
		}
	}

	printf("\n");

	system("pause");
	return 0;
}