Package cc.redberry.combinatorics

Class Combinatorics

java.lang.Object

cc.redberry.combinatorics.Combinatorics

public final class Combinatorics
extends Object

This class provides factory and utility methods for combinatorics infrastructure.

Since:

1.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static interface	Combinatorics.ArrayFactory<T>
private static final class	Combinatorics.GenericFactory<T>
(package private) static final class	Combinatorics.TIterator<T>
(package private) static final class	Combinatorics.TTIterator<T>

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final Comparator<int[]>	arrayComparator

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Combinatorics()

Method Summary

Modifier and Type	Method	Description
static CombinatorialIterator<int[]>	combinations(int n, int k)	Iterator over all k-combinations from {code n}.
static <T> CombinatorialIterator<T[]>	combinations(T[] input, int k)	Iterator over all k-combinations from the specified array
static CombinatorialIterator<int[]>	combinationsWithPermutations(int n, int k)	Iterator over all k-combinations with permutations from {code n}.
static <T> CombinatorialIterator<T[]>	combinationsWithPermutations(T[] input, int k)	Iterator over all k-combinations with permutations from the specified array
static CombinatorialIterator<int[]>	compositions(int integer, int nPartitions)	Iterator over all compositions of integer into nPartitions
private static int[][]	deepClone(int[][] sets)
static CombinatorialIterator<int[]>	distinctTuples(int[]... sets)	Iterator over all distinct N-tuples, which can be chosen from N specified sets of integers.
static <T> CombinatorialIterator<T[]>	distinctTuples(T[]... sets)	Iterator over all N-tuples of elements at different positions, which can be chosen from N specified sets of elements.
private static int[]	indices(int length)
private static <T> T[]	map(T[][] arrays, int[] indices, Combinatorics.ArrayFactory<T> factory)
private static <T> T[]	map(T[] array, int[] indices, Combinatorics.ArrayFactory<T> factory)
static CombinatorialIterator<int[]>	permutations(int n)	Iterator over all permutations of the specified length
static <T> CombinatorialIterator<T[]>	permutations(T[] input)	Iterator over all permutations of the specified array
static CombinatorialIterator<int[]>	tuples(int... bounds)	Iterator over all N-tuples (not necessary to be distinct), which can be chosen from N arrays of integers of the form arrayi = [0, 1, 2, ..., Ki]
static <T> CombinatorialIterator<T[]>	tuples(T[]... sets)	Iterator over all N-tuples, which can be chosen from N specified sets of integers.

Methods inherited from class java.lang.Object

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

Field Details

arrayComparator

static final Comparator<int[]> arrayComparator

Constructor Details

Combinatorics

private Combinatorics()

Method Details

combinations

public static CombinatorialIterator<int[]> combinations(int n,
 int k)

Iterator over all k-combinations from {code n}.

Parameters:

n - combination length

k - the total

combinationsWithPermutations

public static CombinatorialIterator<int[]> combinationsWithPermutations(int n,
 int k)

Iterator over all k-combinations with permutations from {code n}.

Parameters:

n - combination length

k - the total

permutations

public static CombinatorialIterator<int[]> permutations(int n)

Iterator over all permutations of the specified length

compositions

public static CombinatorialIterator<int[]> compositions(int integer,
 int nPartitions)

Iterator over all compositions of integer into nPartitions

Parameters:

integer - the sum

nPartitions - number of partitions

See Also:

• IntCompositions

distinctTuples

public static CombinatorialIterator<int[]> distinctTuples(int[]... sets)

Iterator over all distinct N-tuples, which can be chosen from N specified sets of integers.

Parameters:

sets - array of sets of integers

See Also:

• IntDistinctTuples

deepClone

private static int[][] deepClone(int[][] sets)

tuples

public static CombinatorialIterator<int[]> tuples(int... bounds)

Iterator over all N-tuples (not necessary to be distinct), which can be chosen from N arrays of integers of the form array_i = [0, 1, 2, ..., K_i]

Parameters:

bounds - the bounds on the tuple elements

See Also:

• IntDistinctTuples

map

private static <T> T[] map(T[] array,
 int[] indices,
 Combinatorics.ArrayFactory<T> factory)

permutations

public static <T> CombinatorialIterator<T[]> permutations(T[] input)

Iterator over all permutations of the specified array

combinations

public static <T> CombinatorialIterator<T[]> combinations(T[] input,
 int k)

Iterator over all k-combinations from the specified array

combinationsWithPermutations

public static <T> CombinatorialIterator<T[]> combinationsWithPermutations(T[] input,
 int k)

Iterator over all k-combinations with permutations from the specified array

map

private static <T> T[] map(T[][] arrays,
 int[] indices,
 Combinatorics.ArrayFactory<T> factory)

indices

private static int[] indices(int length)

distinctTuples

public static <T> CombinatorialIterator<T[]> distinctTuples(T[]... sets)

Iterator over all N-tuples of elements at different positions, which can be chosen from N specified sets of elements.

Parameters:

sets - array of sets of integers

See Also:

• IntDistinctTuples

tuples

public static <T> CombinatorialIterator<T[]> tuples(T[]... sets)

Iterator over all N-tuples, which can be chosen from N specified sets of integers.

Parameters:

sets - array of sets of integers

See Also:

• IntDistinctTuples