/****************************************************************************** * Compilation: javac Interval2D.java * Execution: java Interval2D * Dependencies: StdOut.java Interval1D.java StdDraw.java * * 2-dimensional interval data type. * ******************************************************************************/ package edu.princeton.cs.algs4; /** * The {@code Interval2D} class represents a closed two-dimensional interval, * which represents all points (x, y) with both {@code xmin <= x <= xmax} and * {@code ymin <= y <= ymax}. * Two-dimensional intervals are immutable: their values cannot be changed * after they are created. * The class {@code Interval2D} includes methods for checking whether * a two-dimensional interval contains a point and determining whether * two two-dimensional intervals intersect. *

* For additional documentation, * see Section 1.2 of * Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public class Interval2D { private final Interval1D x; private final Interval1D y; /** * Initializes a two-dimensional interval. * @param x the one-dimensional interval of x-coordinates * @param y the one-dimensional interval of y-coordinates */ public Interval2D(Interval1D x, Interval1D y) { this.x = x; this.y = y; } /** * Does this two-dimensional interval intersect that two-dimensional interval? * @param that the other two-dimensional interval * @return true if this two-dimensional interval intersects * that two-dimensional interval; false otherwise */ public boolean intersects(Interval2D that) { if (!this.x.intersects(that.x)) return false; if (!this.y.intersects(that.y)) return false; return true; } /** * Does this two-dimensional interval contain the point p? * @param p the two-dimensional point * @return true if this two-dimensional interval contains the point p; false otherwise */ public boolean contains(Point2D p) { return x.contains(p.x()) && y.contains(p.y()); } /** * Returns the area of this two-dimensional interval. * @return the area of this two-dimensional interval */ public double area() { return x.length() * y.length(); } /** * Returns a string representation of this two-dimensional interval. * @return a string representation of this two-dimensional interval * in the form [xmin, xmax] x [ymin, ymax] */ public String toString() { return x + " x " + y; } /** * Does this interval equal the other interval? * @param other the other interval * @return true if this interval equals the other interval; false otherwise */ public boolean equals(Object other) { if (other == this) return true; if (other == null) return false; if (other.getClass() != this.getClass()) return false; Interval2D that = (Interval2D) other; return this.x.equals(that.x) && this.y.equals(that.y); } /** * Returns an integer hash code for this interval. * @return an integer hash code for this interval */ public int hashCode() { int hash1 = x.hashCode(); int hash2 = y.hashCode(); return 31*hash1 + hash2; } /** * Draws this two-dimensional interval to standard draw. */ public void draw() { double xc = (x.min() + x.max()) / 2.0; double yc = (y.min() + y.max()) / 2.0; StdDraw.rectangle(xc, yc, x.length() / 2.0, y.length() / 2.0); } /** * Unit tests the {@code Interval2D} data type. * * @param args the command-line arguments */ public static void main(String[] args) { double xmin = Double.parseDouble(args[0]); double xmax = Double.parseDouble(args[1]); double ymin = Double.parseDouble(args[2]); double ymax = Double.parseDouble(args[3]); int trials = Integer.parseInt(args[4]); Interval1D xInterval = new Interval1D(xmin, xmax); Interval1D yInterval = new Interval1D(ymin, ymax); Interval2D box = new Interval2D(xInterval, yInterval); box.draw(); Counter counter = new Counter("hits"); for (int t = 0; t < trials; t++) { double x = StdRandom.uniformDouble(0.0, 1.0); double y = StdRandom.uniformDouble(0.0, 1.0); Point2D point = new Point2D(x, y); if (box.contains(point)) counter.increment(); else point.draw(); } StdOut.println(counter); StdOut.printf("box area = %.2f\n", box.area()); } } /****************************************************************************** * Copyright 2002-2022, Robert Sedgewick and Kevin Wayne. * * This file is part of algs4.jar, which accompanies the textbook * * Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne, * Addison-Wesley Professional, 2011, ISBN 0-321-57351-X. * http://algs4.cs.princeton.edu * * * algs4.jar is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * algs4.jar is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with algs4.jar. If not, see http://www.gnu.org/licenses. ******************************************************************************/