edu.princeton.cs.algorithms

Class Interval1D

java.lang.Object

edu.princeton.cs.algorithms.Interval1D

public class Interval1D
extends Object

The Interval1D class represents a one-dimensional closed interval. Intervals are immutable: their values cannot be changed after they are created. The class Interval1D includes methods for checking whether an interval contains a point and determining whether two intervals intersect.

For additional documentation, see Section 1.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Field Summary

Fields

Modifier and Type	Field and Description
static Comparator<Interval1D>	LEFT_ENDPOINT_ORDER Compares two intervals by left endpoint.
static Comparator<Interval1D>	LENGTH_ORDER Compares two intervals by length.
static Comparator<Interval1D>	RIGHT_ENDPOINT_ORDER Compares two intervals by right endpoint.

Constructor Summary

Constructors

Constructor and Description
Interval1D(double left, double right) Initializes an interval [left, right].

Method Summary

Modifier and Type	Method and Description
boolean	contains(double x) Does this interval contain the value x?
boolean	intersects(Interval1D that) Does this interval intersect that interval?
double	left() Returns the left endpoint.
double	length() Returns the length of this interval.
static void	main(String[] args) Unit tests the Interval1D data type.
double	right() Returns the right endpoint.
String	toString() Returns a string representation of this interval.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

LEFT_ENDPOINT_ORDER

public static final Comparator<Interval1D> LEFT_ENDPOINT_ORDER

Compares two intervals by left endpoint.

RIGHT_ENDPOINT_ORDER

public static final Comparator<Interval1D> RIGHT_ENDPOINT_ORDER

Compares two intervals by right endpoint.

LENGTH_ORDER

public static final Comparator<Interval1D> LENGTH_ORDER

Compares two intervals by length.

Constructor Detail

Interval1D

public Interval1D(double left,
                  double right)

Initializes an interval [left, right].

Parameters:

left - the left endpoint

right - the right endpoint

Throws:

IllegalArgumentException - if the left endpoint is greater than the right endpoint

IllegalArgumentException - if either left or right is Double.NaN, Double.POSITIVE_INFINITY or Double.NEGATIVE_INFINITY

Method Detail

left

public double left()

Returns the left endpoint.

Returns:

the left endpoint

right

public double right()

Returns the right endpoint.

Returns:

the right endpoint

intersects

public boolean intersects(Interval1D that)

Does this interval intersect that interval?

Parameters:

that - the other interval

Returns:

true if this interval intersects that interval; false otherwise

contains

public boolean contains(double x)

Does this interval contain the value x?

Parameters:

x - the value

Returns:

true if this interval contains the value x; false otherwise

length

public double length()

Returns the length of this interval.

Returns:

the length of this interval (right - left)

toString

public String toString()

Returns a string representation of this interval.

Overrides:

toString in class Object

Returns:

a string representation of this interval in the form [left, right]

main

public static void main(String[] args)

Unit tests the Interval1D data type.