org.matheclipse.combinatoric

Class RosenIterator

java.lang.Object

org.matheclipse.combinatoric.RosenIterator

All Implemented Interfaces:

java.util.Iterator<int[]>

Direct Known Subclasses:

RosenNumberPartitionIterator

public class RosenIterator
extends java.lang.Object
implements java.util.Iterator<int[]>

An iterator that generates combinations of n elements, C(n), in lexicographic order, based on Rosen's algorithm.

See Also:

"Kenneth H. Rosen, Discrete Mathematics and Its Applications, 2nd edition (NY: McGraw-Hill, 1991), pp. 284-286"

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RosenIterator.Factory

Constructor Summary

Constructors

Constructor and Description
RosenIterator(int n, int k)

Method Summary

Modifier and Type	Method and Description
static long	count(int n, int k) Computes the number of unique combinations of n elements taken k at a time, which can be computed as: n! / k! (n - k)!
boolean	hasNext()
int[]	next()
void	remove()
void	reset()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

RosenIterator

public RosenIterator(int n,
                     int k)

Parameters:

n - the number of elements

k - taken k at a time

Method Detail

reset

public void reset()

count

public static long count(int n,
                         int k)

Computes the number of unique combinations of n elements taken k at a time, which can be computed as: n! / k! (n - k)!

Parameters:

n - the number of elements

k - subset/sample size

Returns:

the number of combinations of n elements taken k at a time

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<int[]>

See Also:

Iterator.hasNext()

next

public int[] next()

Specified by:

next in interface java.util.Iterator<int[]>

See Also:

Iterator.next()

remove

public void remove()

Specified by:

remove in interface java.util.Iterator<int[]>