Cod sursa(job #2015540)

Utilizator mariusn01Marius Nicoli mariusn01 Data 26 august 2017 16:18:58
Problema Rays Scor 70
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.76 kb
#include <cstdio>
#include <fstream>
#include <vector>
#include <stack>
#include <bitset>
#include <algorithm>
#define DIM 200010
#define X first.first
#define Y first.second
#define Z second

using namespace std;

vector<pair<pair<int, int>, int > >S, J;
int n, x1, x2, y, sol;
stack<int> st;
bitset<DIM> B;

int cmp(const pair<pair<int, int>, int > &a, const pair<pair<int, int>, int > & b) {
    long long t = a.X * 1LL * b.Y - a.Y * 1LL * b.X;
    if (t == 0)
        return a.Z < b.Z;
    else
        return t < 0;
}

int main () {

    FILE *fin = fopen("rays.in", "r");
    ofstream fout("rays.out");

    fscanf(fin, "%d", &n);
    for (int i=1;i<=n;i++) {
        fscanf(fin, "%d %d %d", &y, &x1, &x2);
        if (x1 > x2) {
            swap(x1, x2);
        }
        if (y > 0) {
            S.push_back(make_pair(make_pair(x1, y),i));
            S.push_back(make_pair(make_pair(x2, y),-i));
        }else {
            J.push_back(make_pair(make_pair(x1, -y),i));
            J.push_back(make_pair(make_pair(x2, -y),-i));
        }
    }


    for (int t = 2; t--;) {



        sort(S.begin(), S.end(), cmp);

        while (!st.empty())
            st.pop();
        B.reset();

        for (int i=0;i<S.size(); i++) {
            int tip = S[i].Z;
            if (tip > 0) {
                st.push(i);
            } else {
                if (B[-tip] == 0) {
                    sol ++;
                    while (!st.empty()) {
                        B[ S[st.top()].Z ] = 1;
                        st.pop();
                    }
                }
            }
        }

        S.clear();
        for (int i=0;i<J.size();i++)
            S.push_back(J[i]);
    }
    fout<<sol;
    return 0;
}