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package algs32.kdtree;
import algs12.Point2D;
import stdlib.*;

/* ***********************************************************************
 *  Compilation:  javac RectHV.java
 *  Execution:    java RectHV
 *  Dependencies: Point2D.java
 *
 *  Implementation of 2D axis-aligned rectangle.
 *
 *************************************************************************/

public class RectHV {
  private final double xmin, ymin;   // minimum x- and y-coordinates
  private final double xmax, ymax;   // maximum x- and y-coordinates

  // construct the axis-aligned rectangle [xmin, xmax] x [ymin, ymax]
  public RectHV(double xmin, double ymin, double xmax, double ymax) {
    this.xmin = xmin;
    this.ymin = ymin;
    this.xmax = xmax;
    this.ymax = ymax;
    if (xmax < xmin || ymax < ymin) {
      throw new IllegalArgumentException("Invalid rectangle: " + this);
    }
  }

  // accessor methods for 4 coordinates
  public double xmin() { return xmin; }
  public double ymin() { return ymin; }
  public double xmax() { return xmax; }
  public double ymax() { return ymax; }

  // width and height of rectangle
  public double width()  { return xmax - xmin; }
  public double height() { return ymax - ymin; }

  // does this axis-aligned rectangle intersect that one?
  public boolean intersects(RectHV that) {
    return this.xmax >= that.xmin && this.ymax >= that.ymin
        && that.xmax >= this.xmin && that.ymax >= this.ymin;
  }

  // draw this axis-aligned rectangle
  public void draw() {
    StdDraw.line(xmin, ymin, xmax, ymin);
    StdDraw.line(xmax, ymin, xmax, ymax);
    StdDraw.line(xmax, ymax, xmin, ymax);
    StdDraw.line(xmin, ymax, xmin, ymin);
  }

  // distance from p to closest point on this axis-aligned rectangle
  public double distanceTo(Point2D p) {
    return Math.sqrt(this.distanceSquaredTo(p));
  }

  // distance squared from p to closest point on this axis-aligned rectangle
  public double distanceSquaredTo(Point2D p) {
    double dx = 0.0, dy = 0.0;
    if      (p.x() < xmin) dx = p.x() - xmin;
    else if (p.x() > xmax) dx = p.x() - xmax;
    if      (p.y() < ymin) dy = p.y() - ymin;
    else if (p.y() > ymax) dy = p.y() - ymax;
    return dx*dx + dy*dy;
  }

  // does this axis-aligned rectangle contain p?
  public boolean contains(Point2D p) {
    return (p.x() >= xmin) && (p.x() <= xmax)
        && (p.y() >= ymin) && (p.y() <= ymax);
  }

  // are the two axis-aligned rectangles equal?
  public boolean equals(Object y) {
    if (y == this) return true;
    if (y == null) return false;
    if (y.getClass() != this.getClass()) return false;
    final RectHV that = (RectHV) y;
    if (this.xmin != that.xmin) return false;
    if (this.ymin != that.ymin) return false;
    if (this.xmax != that.xmax) return false;
    if (this.ymax != that.ymax) return false;
    return true;
  }

  private int hashCode = 0;
  public int hashCode() {
    int hCode = hashCode;
    if (hCode != 0)
      return hCode;
    int result = 17;
    result = 37*result + Double.hashCode (xmin);
    result = 37*result + Double.hashCode (xmax);
    result = 37*result + Double.hashCode (ymin);
    result = 37*result + Double.hashCode (ymax);
    hashCode = result;
    return result;
  }

  // return a string representation of this axis-aligned rectangle
  public String toString() {
    return "[" + xmin + ", " + xmax + "] x [" + ymin + ", " + ymax + "]";
  }

}