Tema3_geometrie

package geometrie;

import java.io.FileNotFoundException;
import java.util.Scanner;

public class Tema3 {

    public static void main(String[] args) throws FileNotFoundException {

        int POINTS_NUM;
        POINTS_NUM = 4;
        int index = 0;
        boolean result = false;
        boolean done = false;
        Point[] points = new Point[POINTS_NUM];

        //INPUT
        Scanner in = new Scanner(new java.io.File("date.in"));
        for (int j = 0; j < POINTS_NUM; j++) {
            points[j] = new Point(in.nextDouble(), in.nextDouble());
        }
        double a1 = points[0].y - points[1].y;
        double a2 = points[2].y - points[3].y;
        double b1 = points[0].x - points[1].x;
        double b2 = points[2].x - points[3].x;
        double c1 = (points[0].x * points[1].y) - (points[1].x * points[0].y);
        double c2 = (points[2].x * points[3].y) - (points[3].x * points[2].y);

        double delta = (a1 * b2) - (a2 * b1);

        if (delta != 0) {
            double d1 = (c2 * b1) - (c1 * b2);
            double d2 = (a2 * c1) - (a1 * c2);
            Point intersection = new Point(d1 / delta, -d2 / delta);
            if (intersection.between(points[0], points[1]) && intersection.between(points[2], points[3])) {
                System.out.println("Intersection point is = I(" + intersection.x + "," + intersection.y + ")");
            } else {
                System.out.println("Intersection point outside segments");
            }

        } else if (((a1 * c2) - (a2 * c1) != 0) || ((b1 * c2) - (b2 * c1) != 0)) {
            System.out.println("Null intersection");
        } else if ((a1 != 0) && (a2 != 0) && (b1 != 0) && (b2 != 0) && (c2 != 0) && (c1 != 0)) {
            System.out.println("Segments are equal");
        } else {

            Point p0;
            Point p1;
            Point p2;
            Point p3;

            if (points[0].compareTo(points[1]) < 0) {
                p0 = points[0];
                p1 = points[1];
            } else {
                p0 = points[1];
                p1 = points[0];
            }

            if (points[2].compareTo(points[3]) < 0) {
                p2 = points[2];
                p3 = points[3];
            } else {
                p2 = points[3];
                p3 = points[2];
            }

            System.out.println("p0 " + p0);
            System.out.println("p1 " + p1);
            System.out.println("p2 " + p2);
            System.out.println("p3 " + p3);

            if ((p1.compareTo(p2) < 0) || (p3.compareTo(p0) < 0)) {
                System.out.println("Intersection is null.");
                return;
            }

            if (p2.between(p0, p1)) {
                if (p3.between(p0, p1)) {
                    System.out.println("Intersection is [" + p2 + " " + p3 + "]");
                } else {
                    System.out.println("Intersection is [" + p2 + " " + p1 + "]");
                }
            } else {
                if (p3.between(p0, p1)) {
                    System.out.println("Intersection is [" + p0 + " " + p3 + "]");
                } else {
                    System.out.println("Intersection is [" + p0 + " " + p1 + "]");
                }
            }
        }
    }

    static class Point implements Comparable{

        double x, y;

        Point(double x, double y) {
            this.x = x;
            this.y = y;
        }

        boolean between(Point p1, Point p2) {
            double minx = (p1.x < p2.x) ? p1.x : p2.x;
            double maxx = (p1.x > p2.x) ? p1.x : p2.x;
            double miny = (p1.y < p2.y) ? p1.y : p2.y;
            double maxy = (p1.y > p2.y) ? p1.y : p2.y;
            if ((this.x >= minx && this.x <= maxx) && (this.y >= miny && this.y <= maxy)) {
                return true;
            }
            return false;
        }

        @Override
        public int compareTo(Object o) {
            Point p = (Point) o;
            if (x > p.x) {
                return 1;
            } else if (x == p.x) {
                if (y > p.y)
                    return 1;
                else if (y == p.y)
                    return 0;
                else
                    return -1;
            }
            return -1;
        }

        @Override
        public String toString() {
            return "Point{" + "x=" + x + ", y=" + y + '}';
        }

        public Point copy() {
            return new Point(x, y);
        }

        @Override
        public int hashCode() {
            int hash = 7;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (Double.doubleToLongBits(this.x) != Double.doubleToLongBits(other.x)) {
                return false;
            }
            if (Double.doubleToLongBits(this.y) != Double.doubleToLongBits(other.y)) {
                return false;
            }
            return true;
        }


    }
}