[Java] 백준 - 17386번: 선분 교차 1

7월 20일(목) - 기하학 (17386번)

17386번: 선분 교차 1

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문제점

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풀이

(C언어 풀이 활용)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import java.util.StringTokenizer;

public class Main {

    static class point{
        long x;
        long y;
        public point(long x, long y){
            this.x = x;
            this.y = y;
        }
    }

    static int ccw(point a, point b, point c){
        long temp = (a.x * b.y) + (b.x * c.y) + (c.x * a.y);
        temp = temp - (a.y * b.x) - (b.y * c.x) - (c.y * a.x);

        if(temp > 0)
        {
            return 1;
        }
        else if(temp < 0)
        {
            return -1;
        }
        else
        {
            return 0;
        }
    }

    static int cross_or_not(point a, point b, point c, point d){
        int first = ccw(a,b,c) * ccw(a,b,d);
        int second = ccw(c,d,a) * ccw(c,d,b);

        if(first<=0 && second<=0)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }

    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        point a = new point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
        point b = new point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));

        st = new StringTokenizer(br.readLine(), " ");
        point c = new point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
        point d = new point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));

        System.out.println(cross_or_not(a,b,c,d));
    }
}

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