Below is the syntax highlighted version of Interval1D.java.
/****************************************************************************** * Compilation: javac Interval1D.java * Execution: java Interval1D * Dependencies: StdOut.java * * 1-dimensional interval data type. * ******************************************************************************/ package edu.princeton.cs.algs4; import java.util.Arrays; import java.util.Comparator; /** * The {@code Interval1D} class represents a one-dimensional interval. * The interval is <em>closed</em>—it contains both endpoints. * Intervals are immutable: their values cannot be changed after they are created. * The class {@code Interval1D} includes methods for checking whether * an interval contains a point and determining whether two intervals intersect. * <p> * For additional documentation, * see <a href="https://algs4.cs.princeton.edu/12oop">Section 1.2</a> of * <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public class Interval1D { /** * Compares two intervals by min endpoint. */ public static final Comparator<Interval1D> MIN_ENDPOINT_ORDER = new MinEndpointComparator(); /** * Compares two intervals by max endpoint. */ public static final Comparator<Interval1D> MAX_ENDPOINT_ORDER = new MaxEndpointComparator(); /** * Compares two intervals by length. */ public static final Comparator<Interval1D> LENGTH_ORDER = new LengthComparator(); private final double min; private final double max; /** * Initializes a closed interval [min, max]. * * @param min the smaller endpoint * @param max the larger endpoint * @throws IllegalArgumentException if the min endpoint is greater than the max endpoint * @throws IllegalArgumentException if either {@code min} or {@code max} * is {@code Double.NaN}, {@code Double.POSITIVE_INFINITY} or * {@code Double.NEGATIVE_INFINITY} */ public Interval1D(double min, double max) { if (Double.isInfinite(min) || Double.isInfinite(max)) throw new IllegalArgumentException("Endpoints must be finite"); if (Double.isNaN(min) || Double.isNaN(max)) throw new IllegalArgumentException("Endpoints cannot be NaN"); // convert -0.0 to +0.0 if (min == 0.0) min = 0.0; if (max == 0.0) max = 0.0; if (min <= max) { this.min = min; this.max = max; } else throw new IllegalArgumentException("Illegal interval"); } /** * Returns the left endpoint of this interval. * * @return the left endpoint of this interval * @deprecated Replaced by {@link #min()}. */ @Deprecated public double left() { return min; } /** * Returns the right endpoint of this interval. * @return the right endpoint of this interval * @deprecated Replaced by {@link #max()}. */ @Deprecated public double right() { return max; } /** * Returns the min endpoint of this interval. * * @return the min endpoint of this interval */ public double min() { return min; } /** * Returns the max endpoint of this interval. * * @return the max endpoint of this interval */ public double max() { return max; } /** * Returns true if this interval intersects the specified interval. * * @param that the other interval * @return {@code true} if this interval intersects the argument interval; * {@code false} otherwise */ public boolean intersects(Interval1D that) { if (this.max < that.min) return false; if (that.max < this.min) return false; return true; } /** * Returns true if this interval contains the specified value. * * @param x the value * @return {@code true} if this interval contains the value {@code x}; * {@code false} otherwise */ public boolean contains(double x) { return (min <= x) && (x <= max); } /** * Returns the length of this interval. * * @return the length of this interval (max - min) */ public double length() { return max - min; } /** * Returns a string representation of this interval. * * @return a string representation of this interval in the form [min, max] */ public String toString() { return "[" + min + ", " + max + "]"; } /** * Compares this transaction to the specified object. * * @param other the other interval * @return {@code true} if this interval equals the other interval; * {@code false} otherwise */ public boolean equals(Object other) { if (other == this) return true; if (other == null) return false; if (other.getClass() != this.getClass()) return false; Interval1D that = (Interval1D) other; return this.min == that.min && this.max == that.max; } /** * Returns an integer hash code for this interval. * * @return an integer hash code for this interval */ public int hashCode() { int hash1 = ((Double) min).hashCode(); int hash2 = ((Double) max).hashCode(); return 31*hash1 + hash2; } // ascending order of min endpoint, breaking ties by max endpoint private static class MinEndpointComparator implements Comparator<Interval1D> { public int compare(Interval1D a, Interval1D b) { if (a.min < b.min) return -1; else if (a.min > b.min) return +1; else if (a.max < b.max) return -1; else if (a.max > b.max) return +1; else return 0; } } // ascending order of max endpoint, breaking ties by min endpoint private static class MaxEndpointComparator implements Comparator<Interval1D> { public int compare(Interval1D a, Interval1D b) { if (a.max < b.max) return -1; else if (a.max > b.max) return +1; else if (a.min < b.min) return -1; else if (a.min > b.min) return +1; else return 0; } } // ascending order of length private static class LengthComparator implements Comparator<Interval1D> { public int compare(Interval1D a, Interval1D b) { double alen = a.length(); double blen = b.length(); if (alen < blen) return -1; else if (alen > blen) return +1; else return 0; } } /** * Unit tests the {@code Interval1D} data type. * * @param args the command-line arguments */ public static void main(String[] args) { Interval1D[] intervals = new Interval1D[4]; intervals[0] = new Interval1D(15.0, 33.0); intervals[1] = new Interval1D(45.0, 60.0); intervals[2] = new Interval1D(20.0, 70.0); intervals[3] = new Interval1D(46.0, 55.0); StdOut.println("Unsorted"); for (int i = 0; i < intervals.length; i++) StdOut.println(intervals[i]); StdOut.println(); StdOut.println("Sort by min endpoint"); Arrays.sort(intervals, Interval1D.MIN_ENDPOINT_ORDER); for (int i = 0; i < intervals.length; i++) StdOut.println(intervals[i]); StdOut.println(); StdOut.println("Sort by max endpoint"); Arrays.sort(intervals, Interval1D.MAX_ENDPOINT_ORDER); for (int i = 0; i < intervals.length; i++) StdOut.println(intervals[i]); StdOut.println(); StdOut.println("Sort by length"); Arrays.sort(intervals, Interval1D.LENGTH_ORDER); for (int i = 0; i < intervals.length; i++) StdOut.println(intervals[i]); StdOut.println(); } } /****************************************************************************** * 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. ******************************************************************************/