Package cc.redberry.combinatorics

Class IntDistinctTuples

java.lang.Object

cc.redberry.combinatorics.IntDistinctTuples

All Implemented Interfaces:

IntCombinatorialPort, Serializable

public final class IntDistinctTuples
extends Object
implements IntCombinatorialPort

Iterator over all distinct N-tuples, which can be chosen from N sets of integers. More formally, for N integer arrays: array₁, array₂,...,array_N, this class allows to iterate over all possible integer arrays of the form [i₁, i₂,...,i_N], where all numbers numbers i_j are different and i₁ is chosen from array₁, i₂ is chosen from array₂ and so on.

Consider the example:

 int[] a1 = {1, 2, 3};
 int[] a2 = {2, 3};
 IntDistinctTuples tuples = new IntDistinctTuples(a1, a2);
 int[] tuple;
 while ((tuple = tuples.take()) != null)
      System.out.println(Arrays.toString(tuple));
 

This code will produce the following sequence:

 [1, 2]
 [1, 3]
 [2, 3]
 [3, 2]
 

This class is implemented via output port pattern and the calculation of the next tuple occurs only on the invocation of take().

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

Since:

1.0

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface cc.redberry.combinatorics.IntCombinatorialPort

IntCombinatorialPort.Iterator

Field Summary

Fields

Modifier and Type	Field	Description
private final int[]	combination
private final BitSet	previousMask
private static final long	serialVersionUID
private final BitSet[]	setMasks
private byte	state
private final BitSet	temp

Constructor Summary

Constructors

Constructor	Description
IntDistinctTuples(int[]... sets)	Create iterator over distinct tuples formed from the specified arrays (each set will be sorted in place)

Method Summary

Modifier and Type	Method	Description
int[]	getReference()	Returns the reference to the current iteration element
private void	init()
void	reset()	Resets the iteration
int[]	take()	Calculates and returns the next tuple, or null if no more distinct tuples exist.

Methods inherited from class java.lang.Object

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

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

previousMask

private final BitSet previousMask

setMasks

private final BitSet[] setMasks

combination

private final int[] combination

temp

private final BitSet temp

state

private byte state

Constructor Details

IntDistinctTuples

public IntDistinctTuples(int[]... sets)

Create iterator over distinct tuples formed from the specified arrays (each set will be sorted in place)

Method Details

init

private void init()

take

public int[] take()

Calculates and returns the next tuple, or null if no more distinct tuples exist.

Specified by:

take in interface IntCombinatorialPort

Returns:

the next tuple, or null if no more distinct tuples exist

reset

public void reset()

Description copied from interface: IntCombinatorialPort

Resets the iteration

Specified by:

reset in interface IntCombinatorialPort

getReference

public int[] getReference()

Description copied from interface: IntCombinatorialPort

Returns the reference to the current iteration element

Specified by:

getReference in interface IntCombinatorialPort

Returns:

the reference to the current iteration element