Point code

Point.java

/******************************************************************************
 *  Compilation:  javac Point.java
 *  Execution:    java Point
 *  Dependencies: none
 *  
 *  An immutable data type for points in the plane.
 *  For use on Coursera, Algorithms Part I programming assignment.
 *
 ******************************************************************************/
import java.util.Comparator;
import edu.princeton.cs.algs4.StdDraw;

public class Point implements Comparable<Point> {

    private final int x;     // x-coordinate of this point
    private final int y;     // y-coordinate of this point
    public final Comparator<Point> SLOPE_ORDER = new SlopeOrder(); 
    /*
     * Initializes a new point.
     *
     * @param  x the <em>x</em>-coordinate of the point
     * @param  y the <em>y</em>-coordinate of the point
     */

    private class SlopeOrder implements Comparator<Point> {
        
        public int compare(Point point1, Point point2) {
            double slope1 = slopeTo(point1);
            double slope2 = slopeTo(point2);

            if(slope1 > slope2){
                return 1;
            }

            else if(slope1 < slope2) {
                return -1;
            }

            return 0;
        }
    }

    public Point(int x, int y) {
        /* DO NOT MODIFY */
        this.x = x;
        this.y = y;
    }
    

    /*
     * Draws this point to standard draw.
     */
    public void draw() {
        /* DO NOT MODIFY */
        StdDraw.point(x, y);
    }

    /*
     * Draws the line segment between this point and the specified point
     * to standard draw.
     *
     * @param that the other point
     */

    public void drawTo(Point that) {
        /* DO NOT MODIFY */
        StdDraw.line(this.x, this.y, that.x, that.y);
    }

    /*
     * Returns the slope between this point and the specified point.
     * Formally, if the two points are (x0, y0) and (x1, y1), then the slope
     * is (y1 - y0) / (x1 - x0). For completeness, the slope is defined to be
     * +0.0 if the line segment connecting the two points is horizontal;
     * Double.POSITIVE_INFINITY if the line segment is vertical;
     * and Double.NEGATIVE_INFINITY if (x0, y0) and (x1, y1) are equal.
     *
     * @param  that the other point
     * @return the slope between this point and the specified point
     */
    public double slopeTo(Point that) {
        
        double deltaY = that.y - this.y;
        double deltaX = that.x - this.x;
        
        if (deltaX == 0 && deltaY == 0) {
            return Double.NEGATIVE_INFINITY; 
        } 
        
        if(deltaX == 0) {
            return Double.POSITIVE_INFINITY; 
        }
        
        if(deltaY == 0) {
            return 0.0;
        }
    

        return deltaY/deltaX;
    }

    /*
     * Compares two points by y-coordinate, breaking ties by x-coordinate.
     * Formally, the invoking point (x0, y0) is less than the argument point
     * (x1, y1) if and only if either y0 < y1 or if y0 = y1 and x0 < x1.
     *
     * @param  that the other point
     * @return the value 0< if this point is equal to the argument
     *         point (x0 = x1 and y0 = y1);
     *         a negative integer if this point is less than the argument
     *         point; and a positive integer if this point is greater than the
     *         argument pointb
     */
    
    private boolean less(int p1, int p2) { 
        return p1 < p2;
    }

    private boolean greater(int p1, int p2) {
        return p1 > p2;
    }
    
    public int compareTo(Point that) {
        
            if (less(this.y, that.y)) {
                return -1;
            }
            else if (greater(this.y, that.y)) {
                return 1;
            }
            else if (greater(that.x, this.x)) {
                return -1;
            }
            else if(greater(this.x, that.x)) {
                return 1;
            }
            else {
                return 0;
            }
    }
    /*
     * Compares two points by the slope they make with this point.
     * The slope is defined as in the slopeTo() method.
     *
     * @return the Comparator that defines this ordering on points
     */
    /*
     * Returns a string representation of this point.
     * This method is provide for debugging;
     * your program should not rely on the format of the string representation.
     *
     * @return a string representation of this point
     */
    public String toString() {
        /* DO NOT MODIFY */
        return "(" + x + ", " + y + ")";
    }
}