cc.redberry.combinatorics

Class IntCombinationsWithPermutations

java.lang.Object

cc.redberry.combinatorics.IntCombinationsWithPermutations

All Implemented Interfaces:

CombinatorialIterator<int[]>, Serializable, Iterable<int[]>, Iterator<int[]>

public final class IntCombinationsWithPermutations
extends Object

Iterator over over all possible unique combinations with permutations (i.e. {0,1} and {1,0} both will appear in the iteration) of k numbers, which can be chosen from the set of n numbers (0,1,2,...,n). The total number of such combinations will be n!/(n-k)!.

For example, for k=2 and n=3, it will produce the following arrays sequence: [0,1], [1,0], [0,2], [2,0], [1,2], [2,1].

The iterator is implemented such that each next combination will be calculated only on the invocation of method next() (no pre-calculation of results).

Note: method next() returns the same reference on each invocation.

Internally this class uses combination of IntCombinations and IntPermutations.

Since:

1.0

Author:

Dmitry Bolotin, Stanislav Poslavsky

See Also:

IntCombinations, IntPermutations, Serialized Form

Constructor Summary

Constructors

Constructor and Description
IntCombinationsWithPermutations(int n, int k) Constructs the iterator with the desired n and k

Method Summary

Modifier and Type	Method and Description
int[]	current() Returns the reference on the current iteration element.
boolean	hasNext()
int[]	next() Calculates and returns the next combination.
void	remove() Throws UnsupportedOperationException.
void	reset() Resets the iteration
List<int[]>	toList() Write all elements of this iterable to list

Methods inherited from class java.lang.Object

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

Methods inherited from interface cc.redberry.combinatorics.CombinatorialIterator

iterator, stream

Methods inherited from interface java.util.Iterator

forEachRemaining

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

IntCombinationsWithPermutations

public IntCombinationsWithPermutations(int n,
                                       int k)

Constructs the iterator with the desired n and k

Method Detail

hasNext

public boolean hasNext()

next

public int[] next()

Calculates and returns the next combination.

Returns:

the next combination

remove

public void remove()

Throws UnsupportedOperationException.

reset

public void reset()

Description copied from interface: CombinatorialIterator

Resets the iteration

current

public int[] current()

Description copied from interface: CombinatorialIterator

Returns the reference on the current iteration element.

Returns:

the reference on the current iteration element

toList

public final List<int[]> toList()

Description copied from interface: CombinatorialIterator

Write all elements of this iterable to list

Specified by:

toList in interface CombinatorialIterator<int[]>