edu.princeton.cs.algorithms

Class Edge

java.lang.Object

edu.princeton.cs.algorithms.Edge

All Implemented Interfaces:

Comparable<Edge>

public class Edge
extends Object
implements Comparable<Edge>

The Edge class represents a weighted edge in an EdgeWeightedGraph. Each edge consists of two integers (naming the two vertices) and a real-value weight. The data type provides methods for accessing the two endpoints of the edge and the weight. The natural order for this data type is by ascending order of weight.

For additional documentation, see Section 4.3 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Constructor Summary

Constructors

Constructor and Description
Edge(int v, int w, double weight) Initializes an edge between vertices v/tt> and w of the given weight.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Edge that) Compares two edges by weight.
int	either() Returns either endpoint of the edge.
static void	main(String[] args) Unit tests the Edge data type.
int	other(int vertex) Returns the endpoint of the edge that is different from the given vertex (unless the edge represents a self-loop in which case it returns the same vertex).
String	toString() Returns a string representation of the edge.
double	weight() Returns the weight of the edge.

Methods inherited from class java.lang.Object

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

Constructor Detail

Edge

public Edge(int v,
            int w,
            double weight)

Initializes an edge between vertices v/tt> and w of the given weight. param v one vertex param w the other vertex param weight the weight of the edge

Throws:

IndexOutOfBoundsException - if either v or w is a negative integer

IllegalArgumentException - if weight is NaN

Method Detail

weight

public double weight()

Returns the weight of the edge.

Returns:

the weight of the edge

either

public int either()

Returns either endpoint of the edge.

Returns:

either endpoint of the edge

other

public int other(int vertex)

Returns the endpoint of the edge that is different from the given vertex (unless the edge represents a self-loop in which case it returns the same vertex).

Parameters:

vertex - one endpoint of the edge

Returns:

the endpoint of the edge that is different from the given vertex (unless the edge represents a self-loop in which case it returns the same vertex)

Throws:

IllegalArgumentException - if the vertex is not one of the endpoints of the edge

compareTo

public int compareTo(Edge that)

Compares two edges by weight.

Specified by:

compareTo in interface Comparable<Edge>

Parameters:

that - the other edge

Returns:

a negative integer, zero, or positive integer depending on whether this edge is less than, equal to, or greater than that edge

toString

public String toString()

Returns a string representation of the edge.

Overrides:

toString in class Object

Returns:

a string representation of the edge

main

public static void main(String[] args)

Unit tests the Edge data type.