cc.redberry.combinatorics

Class IntCombinations

java.lang.Object

cc.redberry.combinatorics.IntCombinations

All Implemented Interfaces:

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

public final class IntCombinations
extends Object

Iterator over all unordered combinations (i.e. [0,1] and [1,0] are considered as same, so only [0,1] will appear in the sequence) of k numbers, which can be chosen from the set of n numbers (0,1,2,...,n). The total number of such combinations is a binomial coefficient n!/(k!(n-k)!). Each returned array is sorted.

The iterator is implemented such that each next combination will be calculated only on the invocation of method next().

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

Since:

1.0

Author:

Dmitry Bolotin, Stanislav Poslavsky

See Also:

IntCombinationsWithPermutations, Serialized Form

Constructor Summary

Constructors

Constructor and Description
IntCombinations(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()
void	remove()
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

IntCombinations

public IntCombinations(int n,
                       int k)

Constructs the iterator with the desired n and k

Method Detail

hasNext

public boolean hasNext()

reset

public void reset()

Description copied from interface: CombinatorialIterator

Resets the iteration

next

public int[] next()

remove

public void remove()

Throws:

UnsupportedOperationException - always

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[]>