Cod sursa(job #114559)

Utilizator dominoMircea Pasoi domino Data 14 decembrie 2007 20:48:57
Problema Rays Scor Ascuns
Compilator cpp Status done
Runda Marime 1.01 kb
#include <stdio.h>
#include <math.h>
#include <algorithm>

using namespace std;

#define MAX_N 200005
#define FIN "rays.in"
#define FOUT "rays.out"
#define mp make_pair
#define f first
#define s second

typedef pair<double, double> entry;

int N, na, nb;
entry A[MAX_N], B[MAX_N];

int solve(entry A[], int N)
{
    int i, ret = 1;
    double last;
    
    sort(A, A+N);
    last = A[0].f;
    for (i = 1; i < N; ++i)
        if (last < A[i].s)
        {
            last = A[i].f;
            ++ret;
        }
    return ret;
}

int main(void)
{
    int i, x, y1, y2;
    entry e;

    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);

    scanf("%d", &N);
    for (i = 0; i < N; ++i)
    {
        scanf("%d %d %d", &x, &y1, &y2);
        e = mp(atan2(y1, x), atan2(y2, x));
        if (e.f < e.s) swap(e.f, e.s);
        if (x < 0)
            A[na++] = e;
        else
            B[nb++] = e;
    }
    printf("%d\n", solve(A, na)+solve(B, nb));

    return 0;
}