PAT1002

#include "iostream"
#include "map"
#include "set"
#include "vector"
using namespace std;
map<int, double> res;
set<int> set_ex;
int k, ex;
double co;
int main()
{
     
    cin >> k;
    while (k-- > 0)
    {
     
        cin >> ex >> co;
        if (res.find(ex) != res.end())
            res[ex] += co;
        else
            res[ex] = co;
        if (set_ex.find(ex) == set_ex.end())
            set_ex.insert(ex);
    }
    cin >> k;
    while (k-- > 0)
    {
     
        cin >> ex >> co;
        if (res.find(ex) != res.end())
            res[ex] += co;
        else
            res[ex] = co;
        if (set_ex.find(ex) == set_ex.end() && res[ex] != 0)
            set_ex.insert(ex);
        if(set_ex.find(ex)!=set_ex.end()&&res[ex]==0)
            set_ex.erase(set_ex.find(ex));
    }
    cout << set_ex.size();
    if (set_ex.size() == 0)
        return 0;
    for (auto it = set_ex.rbegin(); it != set_ex.rend(); it++)
    {
     
        cout << " ";
        printf("%d", *it);
        cout << " ";
        printf("%.1lf", res[*it]);
    }
    return 0;
}
//#1    2 1 1.0 2 1.0   2 1 1.0 2 1.0
//#2    0               0
//#3    10
//#4    2 1 2.4 0 3.2 2 2 1.5 1 0.5
//#5    2 1.1 2.4 0.1 3.2 2 1.1 1.5 2.1 1.5
//#6    1 1 1.0 1 1 -1.0当系数为0时不算一项
//这一题主要是当系数为0时它不算一项了
//我是菜鸡