Досье орбитальной атаки

#include <iostream>
#include <conio.h>
#include <math.h>
#include <string>
#include <algorithm>
#include <set>

using namespace ::std;

struct pos
{
    int x, y;
};

bool operator<(pos p1, pos p2)
{
    if (p1.x == p2.x)
        return p1.y < p2.y;
    else
        return p1.x < p2.x;
}
int main()
{
    int maxx=0, maxy=0, minx=0, miny=0, n;
    set <pos> kil;

    cin >> n;

    for (int i = 1; i <= n; i++)
    {
        int x, y;
        pos prom;
        cin >> x >> y;
        prom.x = x;
        prom.y = y;
        kil.insert(prom);
        if (x > maxx)
            maxx = x;
        if (x < minx)
            minx = x;
        if (y > maxy)
            maxy = y;
        if (y < miny)
            miny= y;
    }

    for (int y = maxy; y >= miny; y--)
    {
        for (int x = minx; x <= maxx; x++)
        {
            pos prom;
            prom.x = x;
            prom.y = y;
            if (kil.find(prom) != kil.end())
                cout << "*";
            else
                if (x == 0 && y != 0)
                    cout << "|";
                else
                    if (x != 0 && y == 0)
                        cout << "-";
                    else
                        if (y == 0 && x == 0)
                            cout << "+";
                        else
                            cout << ".";
        }
        cout << endl;
    }


    return 0;
}