Forest

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
//package kilo.v2.t2;

import java.util.ArrayList;
import java.util.Iterator;

/**
 *
 * @author asjuvone
 */
public class KILOV2T2 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        IO io = new IO();

        int n = io.nextInt();

        int uloeviX = io.nextInt();
        int uloeviY = io.nextInt();

        Pari uolevi = new Pari(uloeviX, uloeviY);

        int nakee = n;
        ArrayList<Pari> parit = new ArrayList();

        for (int i = 0; i < n; i++) {
            int x = io.nextInt();
            int y = io.nextInt();
            Pari uus = new Pari(x, y);
            parit.add(uus);
        }

        for (Iterator<Pari> it = parit.iterator(); it.hasNext();) {
            Pari pari = it.next();
            for (Pari piste : parit) {
                if (piste.equals(pari)) continue;
                if (onksPisteSuoral(piste, pari, uolevi)) {
                    nakee--;
                    it.remove();
                    break;
                }
            }
        }

        System.out.println(parit.size());

    }

    static boolean onksPisteSuoral(Pari piste, Pari suora1, Pari suora2) {
        
        if (piste.y < Math.max(suora1.y, suora2.y) 
                && piste.x > Math.min(suora1.x, suora2.x)
                && piste.y > Math.min(suora1.y, suora2.y)
                && piste.x < Math.max(suora1.x, suora2.x)) {
            if (piste.y == (suora1.x * suora2.y) / suora2.x ) {
                return true;
            }
        }
        return false;
        
        
        
    }
    
    
//    static boolean onkoPisteSuoralla(Pari piste, Pari suora1, Pari suora2) {
//        //Lasketaan pisteen etäisyys suorasta ja jos se on 0 niin true, muuten false;
//        int x1 = suora1.x;
//        int x2 = suora2.x;
//        int y1 = suora1.y;
//        int y2 = suora2.y;
//        int x3 = piste.x;
//        int y3 = piste.y;
//
//        double ylaosa = Math.abs((x1 * y2) - (x2 * y1) + (x2 * y3) - (x3 - y2) + (x3 * y1) - (x1 * y3));
//
//        double alaosa = (Math.pow(suora1.x - suora2.x, 2) + Math.pow(suora1.y - suora2.y, 2));
//        System.out.println(ylaosa / alaosa);
//        return (ylaosa / alaosa) < 0.05;
//    }

}

class Pari {

    long x;
    long y;

    public Pari(long x, long y) {
        this.x = x;
        this.y = y;
    }

}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: WRONG ANSWER