Cod sursa(job #1699856)

Utilizator akaprosAna Kapros akapros Data 8 mai 2016 17:52:07
Problema Oypara Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.11 kb
#include <bits/stdc++.h>
#define maxN 100002
#define inf 1000000000
using namespace std;
int n, a1, a2;
double b1, b2, Q;
struct line
{
    int x, y1, y2;
} v[maxN];
double Fabs(double x)
{
    if (x < 0)
        return -x;
    return x;
}
int Z(double x)
{
    if ((x - ((int)(x))) < ((int)(x) + 1 - x))
        return (int)(x);
    return (int)(x) + 1;
}
void read()
{
    int i;
    freopen("oypara.in", "r", stdin);
    scanf("%d", &n);
    for (i = 1; i <= n; ++ i)
        scanf("%d %d %d", &v[i].x, &v[i].y2, &v[i].y1);
}
int ok(double m)
{
    int i;
    double x = -m * v[1].x + v[1].y1,
           y = -m * v[1].x + v[1].y2;
    for (i = 2; i <= n; ++ i)
    {
        double cx, cy;
        cx = -m * v[i].x + v[i].y1;
        cy = -m * v[i].x + v[i].y2;
        if (cx < x)
        {
            x = cx;
            if (x < y)
                return -1;
        }
        if (cy > y)
        {
            y = cy;
            if (x < y)
                return 1;
        }
    }
    Q = (x + y) / 2;
    return 0;
}
double bs()
{
    double l = -inf, r = inf, mid;
    while (l < r)
    {
        mid = (l + r) / 2;
        if (mid < 1)
        {
            int ak = 47;
        }
        int q = ok(mid);
        if (q == 0)
            break;
        if (q == 1)
            l = mid;
        else
            r = mid;
    }

    return mid;
}
void solve()
{
    int i;
    double m = bs();
    a1 = v[1].x, a2 = v[2].x;
    b1 = m * v[1].x + Q, b2 = m * v[2].x + Q;
    for (i = 3; i <= n; ++ i)
    {
        double b = m * v[i].x + Q;

        if (Fabs(b - (double)(Z(b))) < Fabs(b1 - (double)(Z(b1))))
        {
            a2 = a1;
            a1 = v[i].x;
            b2 = b1;
            b1 = b;
        }
        else if (Fabs(b - (double)(Z(b))) < Fabs(b2 - (double)(Z(b2))))
        {
            a2 = v[i].x;
            b2 = b;
        }
    }
}
void write()
{
    freopen("oypara.out", "w", stdout);
    printf("%d %d %d %d", a1, Z(b1), a2, Z(b2));
}
int main()
{
    read();
    solve();
    write();
    return 0;
}