Cod sursa(job #2207528)

Utilizator Ruxandra985Nanu Ruxandra Laura Ruxandra985 Data 25 mai 2018 21:39:33
Problema Rays Scor 60
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.05 kb
#include <cstdio>
#include <algorithm>

using namespace std;
struct segm{
    double tan;
    int tip;
    int poz;
};
segm st[400001],dr[400001];
int f[200001];
inline double modul (double x){
    if (x>=1.0 * 0)
        return x;
    return -x;
}
inline int cmp (segm x,segm y){
    if (modul(x.tan-y.tan)<(double)0.0000001)
        return x.tip>y.tip;
    return x.tan<y.tan;
}
int main()
{
    FILE *fin=fopen ("rays.in","r");
    FILE *fout=fopen ("rays.out","w");
    int n,elim,sol,i,ss,sd;
    int x,y1,y2;
    fscanf (fin,"%d",&n);
    ss=sd=0;
    for (i=1;i<=n;i++){
        fscanf (fin,"%d%d%d",&x,&y1,&y2);
        if (y1>y2)
            swap(y1,y2);
        if (x<0){
            st[++ss].tan=-(1.0*y1)/x;
            st[ss].tip=1; // incepe un segment
            st[ss].poz=i;
            st[++ss].tan=-(1.0*y2)/x;
            st[ss].tip=0; // se termina un segment
            st[ss].poz=i;
        }
        else{
            dr[++sd].tan=(1.0*y1)/x;
            dr[sd].tip=1; // incepe un segment
            dr[sd].poz=i;
            dr[++sd].tan=(1.0*y2)/x;
            dr[sd].tip=0; // se termina un segment
            dr[sd].poz=i;
        }
    }
    // este gresit sa incerc sa normalizez
    sort (st+1,st+ss+1,cmp); // am sortat dupa unghiul cu ox
    sort (dr+1,dr+sd+1,cmp);
    sol=0;
    elim=0;
    for (i=1;i<=ss;i++){
        if (st[i].tip==1) // eveniment 1 : incepe un segment
            f[st[i].poz]=i;
        else {// eveniment 2 : se termina un segment
            if (f[st[i].poz]>elim){ // daca nu l am anulat cu alta ocazie
                sol++;
                elim=i;
            }
        }
    }
    elim=0;
    for (i=1;i<=sd;i++){
        if (dr[i].tip==1) // eveniment 1 : incepe un segment
            f[dr[i].poz]=i;
        else {// eveniment 2 : se termina un segment
            if (f[dr[i].poz]>elim){ // daca nu l am anulat cu alta ocazie
                sol++;
                elim=i;
            }
        }
    }
    fprintf (fout,"%d",sol);
    return 0;
}