edu.princeton.cs.algs4.Interval2D Maven / Gradle / Ivy
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/******************************************************************************
* 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.uniform(0.0, 1.0);
double y = StdRandom.uniform(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 2002-2018, 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.
******************************************************************************/