it.unimi.dsi.fastutil.booleans.BooleanArrays

public final class BooleanArrays extends Object

A class providing static methods and objects that do useful things with type-specific arrays.

In particular, the forceCapacity(), ensureCapacity(), grow(), trim() and setLength() methods allow to handle arrays much like array lists. This can be very useful when efficiency (or syntactic simplicity) reasons make array lists unsuitable.

Note that BinIO and TextIO contain several methods make it possible to load and save arrays of primitive types as sequences of elements in DataInput format (i.e., not as objects) or as sequences of lines of text.

Sorting

There are several sorting methods available. The main theme is that of letting you choose the sorting algorithm you prefer (i.e., trading stability of mergesort for no memory allocation in quicksort).

Parallel operations

Some algorithms provide a parallel version that will by default use the common pool, but this can be overridden by calling the function in a task already in the ForkJoinPool that the operation should run in. For example, something along the lines of "poolToParallelSortIn.invoke(() -> parallelQuickSort(arrayToSort))" will run the parallel sort in poolToParallelSortIn instead of the default pool. Some algorithms also provide an explicit indirect sorting facility, which makes it possible to sort an array using the values in another array as comparator.

However, if you wish to let the implementation choose an algorithm for you, both stableSort(boolean[], int, int) and unstableSort(boolean[], int, int) methods are available, which dynamically chooses an algorithm based on unspecified criteria (but most likely stability, array size, and array element type).

All comparison-based algorithm have an implementation based on a type-specific comparator.

As a general rule, sequential radix sort is significantly faster than quicksort or mergesort, in particular on random-looking data. In the parallel case, up to a few cores parallel radix sort is still the fastest, but at some point quicksort exploits parallelism better.

If you are fine with not knowing exactly which algorithm will be run (in particular, not knowing exactly whether a support array will be allocated), the dual-pivot parallel sorts in Arrays are about 50% faster than the classical single-pivot implementation used here.

In any case, if sorting time is important I suggest that you benchmark your sorting load with your data distribution and on your architecture.

See Also:

Field Summary

Fields

Modifier and Type

Field

Description

static final boolean[]

DEFAULT_EMPTY_ARRAY

A static, final, empty array to be used as default array in allocations.

static final boolean[]

EMPTY_ARRAY

A static, final, empty array.

static final Hash.Strategy<boolean[]>

HASH_STRATEGY

A type-specific content-based hash strategy for arrays.
Method Summary

Modifier and Type

Method

Description

static boolean[]

copy(boolean[] array)

Returns a copy of an array.

static boolean[]

copy(boolean[] array, int offset, int length)

Returns a copy of a portion of an array.

static boolean[]

ensureCapacity(boolean[] array, int length)

Ensures that an array can contain the given number of entries.

static boolean[]

ensureCapacity(boolean[] array, int length, int preserve)

Ensures that an array can contain the given number of entries, preserving just a part of the array.

static void

ensureFromTo(boolean[] a, int from, int to)

Ensures that a range given by its first (inclusive) and last (exclusive) elements fits an array.

static void

ensureOffsetLength(boolean[] a, int offset, int length)

Ensures that a range given by an offset and a length fits an array.

static void

ensureSameLength(boolean[] a, boolean[] b)

Ensures that two arrays are of the same length.

static boolean

equals(boolean[] a1, boolean[] a2)

Deprecated.
Please use the corresponding Arrays method, which is intrinsified in recent JVMs.

static void

fill(boolean[] array, boolean value)

Deprecated.
Please use the corresponding Arrays method.

static void

fill(boolean[] array, int from, int to, boolean value)

Deprecated.
Please use the corresponding Arrays method.

static boolean[]

forceCapacity(boolean[] array, int length, int preserve)

Forces an array to contain the given number of entries, preserving just a part of the array.

static boolean[]

grow(boolean[] array, int length)

Grows the given array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length.

static boolean[]

grow(boolean[] array, int length, int preserve)

Grows the given array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length, preserving just a part of the array.

static void

mergeSort(boolean[] a)

Sorts an array according to the natural ascending order using mergesort.

static void

mergeSort(boolean[] a, int from, int to)

Sorts the specified range of elements according to the natural ascending order using mergesort.

static void

mergeSort(boolean[] a, int from, int to, boolean[] supp)

Sorts the specified range of elements according to the natural ascending order using mergesort, using a given pre-filled support array.

static void

mergeSort(boolean[] a, int from, int to, BooleanComparator comp)

Sorts the specified range of elements according to the order induced by the specified comparator using mergesort.

static void

mergeSort(boolean[] a, int from, int to, BooleanComparator comp, boolean[] supp)

Sorts the specified range of elements according to the order induced by the specified comparator using mergesort, using a given pre-filled support array.

static void

mergeSort(boolean[] a, BooleanComparator comp)

Sorts an array according to the order induced by the specified comparator using mergesort.

static void

parallelQuickSort(boolean[] x)

Sorts an array according to the natural ascending order using a parallel quicksort.

static void

parallelQuickSort(boolean[] x, boolean[] y)

Sorts two arrays according to the natural lexicographical ascending order using a parallel quicksort.

static void

parallelQuickSort(boolean[] x, boolean[] y, int from, int to)

Sorts the specified range of elements of two arrays according to the natural lexicographical ascending order using a parallel quicksort.

static void

parallelQuickSort(boolean[] x, int from, int to)

Sorts the specified range of elements according to the natural ascending order using a parallel quicksort.

static void

parallelQuickSort(boolean[] x, int from, int to, BooleanComparator comp)

Sorts the specified range of elements according to the order induced by the specified comparator using a parallel quicksort.

static void

parallelQuickSort(boolean[] x, BooleanComparator comp)

Sorts an array according to the order induced by the specified comparator using a parallel quicksort.

static void

parallelQuickSortIndirect(int[] perm, boolean[] x)

Sorts an array according to the natural ascending order using a parallel indirect quicksort.

static void

parallelQuickSortIndirect(int[] perm, boolean[] x, int from, int to)

Sorts the specified range of elements according to the natural ascending order using a parallel indirect quicksort.

static void

quickSort(boolean[] x)

Sorts an array according to the natural ascending order using quicksort.

static void

quickSort(boolean[] x, boolean[] y)

Sorts two arrays according to the natural lexicographical ascending order using quicksort.

static void

quickSort(boolean[] x, boolean[] y, int from, int to)

Sorts the specified range of elements of two arrays according to the natural lexicographical ascending order using quicksort.

static void

quickSort(boolean[] x, int from, int to)

Sorts the specified range of elements according to the natural ascending order using quicksort.

static void

quickSort(boolean[] x, int from, int to, BooleanComparator comp)

Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.

static void

quickSort(boolean[] x, BooleanComparator comp)

Sorts an array according to the order induced by the specified comparator using quicksort.

static void

quickSortIndirect(int[] perm, boolean[] x)

Sorts an array according to the natural ascending order using indirect quicksort.

static void

quickSortIndirect(int[] perm, boolean[] x, int from, int to)

Sorts the specified range of elements according to the natural ascending order using indirect quicksort.

static boolean[]

reverse(boolean[] a)

Reverses the order of the elements in the specified array.

static boolean[]

reverse(boolean[] a, int from, int to)

Reverses the order of the elements in the specified array fragment.

static boolean[]

setLength(boolean[] array, int length)

Sets the length of the given array.

static boolean[]

shuffle(boolean[] a, int from, int to, Random random)

Shuffles the specified array fragment using the specified pseudorandom number generator.

static boolean[]

shuffle(boolean[] a, Random random)

Shuffles the specified array using the specified pseudorandom number generator.

static void

stabilize(int[] perm, boolean[] x)

Stabilizes a permutation.

static void

stabilize(int[] perm, boolean[] x, int from, int to)

Stabilizes a permutation.

static void

stableSort(boolean[] a)

Sorts the specified range of elements according to the natural ascending order potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

stableSort(boolean[] a, int from, int to)

Sorts an array according to the natural ascending order, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

stableSort(boolean[] a, int from, int to, BooleanComparator comp)

Sorts the specified range of elements according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

stableSort(boolean[] a, BooleanComparator comp)

Sorts an array according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

swap(boolean[] x, int a, int b)

Swaps two elements of an anrray.

static void

swap(boolean[] x, int a, int b, int n)

Swaps two sequences of elements of an array.

static boolean[]

trim(boolean[] array, int length)

Trims the given array to the given length.

static void

unstableSort(boolean[] a)

Sorts the specified range of elements according to the natural ascending order potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

unstableSort(boolean[] a, int from, int to)

Sorts an array according to the natural ascending order, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

unstableSort(boolean[] a, int from, int to, BooleanComparator comp)

Sorts the specified range of elements according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

static void

unstableSort(boolean[] a, BooleanComparator comp)

Sorts an array according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- EMPTY_ARRAY
  
  public static final boolean[] EMPTY_ARRAY
  
  A static, final, empty array.
- DEFAULT_EMPTY_ARRAY
  
  public static final boolean[] DEFAULT_EMPTY_ARRAY
  
  A static, final, empty array to be used as default array in allocations. An object distinct from EMPTY_ARRAY makes it possible to have different behaviors depending on whether the user required an empty allocation, or we are just lazily delaying allocation.
  See Also:
  
  ArrayList
- HASH_STRATEGY
  
  public static final Hash.Strategy<boolean[]> HASH_STRATEGY
  
  A type-specific content-based hash strategy for arrays.
  This hash strategy may be used in custom hash collections whenever keys are arrays, and they must be considered equal by content. This strategy will handle null correctly, and it is serializable.
Method Details
- forceCapacity
  
  public static boolean[] forceCapacity(boolean[] array, int length, int preserve)
  
  Forces an array to contain the given number of entries, preserving just a part of the array.
  
  Parameters:
  
  array - an array.
  
  length - the new minimum length for this array.
  
  preserve - the number of elements of the array that must be preserved in case a new allocation is necessary.
  
  Returns:
  
  an array with length entries whose first preserve entries are the same as those of array.
- ensureCapacity
  
  public static boolean[] ensureCapacity(boolean[] array, int length)
  
  Ensures that an array can contain the given number of entries.
  If you cannot foresee whether this array will need again to be enlarged, you should probably use grow() instead.
  
  Parameters:
  
  array - an array.
  
  length - the new minimum length for this array.
  
  Returns:
  
  array, if it contains length entries or more; otherwise, an array with length entries whose first array.length entries are the same as those of array.
- ensureCapacity
  
  public static boolean[] ensureCapacity(boolean[] array, int length, int preserve)
  
  Ensures that an array can contain the given number of entries, preserving just a part of the array.
  
  Parameters:
  
  array - an array.
  
  length - the new minimum length for this array.
  
  preserve - the number of elements of the array that must be preserved in case a new allocation is necessary.
  
  Returns:
  
  array, if it can contain length entries or more; otherwise, an array with length entries whose first preserve entries are the same as those of array.
- grow
  
  public static boolean[] grow(boolean[] array, int length)
  
  Grows the given array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length.
  If you want complete control on the array growth, you should probably use ensureCapacity() instead.
  
  Parameters:
  
  array - an array.
  
  length - the new minimum length for this array.
  
  Returns:
  
  array, if it can contain length entries; otherwise, an array with max(length,array.length/φ) entries whose first array.length entries are the same as those of array.
- grow
  
  public static boolean[] grow(boolean[] array, int length, int preserve)
  
  Grows the given array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length, preserving just a part of the array.
  If you want complete control on the array growth, you should probably use ensureCapacity() instead.
  
  Parameters:
  
  array - an array.
  
  length - the new minimum length for this array.
  
  preserve - the number of elements of the array that must be preserved in case a new allocation is necessary.
  
  Returns:
  
  array, if it can contain length entries; otherwise, an array with max(length,array.length/φ) entries whose first preserve entries are the same as those of array.
- trim
  
  public static boolean[] trim(boolean[] array, int length)
  
  Trims the given array to the given length.
  
  Parameters:
  
  array - an array.
  
  length - the new maximum length for the array.
  
  Returns:
  
  array, if it contains length entries or less; otherwise, an array with length entries whose entries are the same as the first length entries of array.
- setLength
  
  public static boolean[] setLength(boolean[] array, int length)
  
  Sets the length of the given array.
  
  Parameters:
  
  array - an array.
  
  length - the new length for the array.
  
  Returns:
  
  array, if it contains exactly length entries; otherwise, if it contains more than length entries, an array with length entries whose entries are the same as the first length entries of array; otherwise, an array with length entries whose first array.length entries are the same as those of array.
- copy
  
  public static boolean[] copy(boolean[] array, int offset, int length)
  
  Returns a copy of a portion of an array.
  
  Parameters:
  
  array - an array.
  
  offset - the first element to copy.
  
  length - the number of elements to copy.
  
  Returns:
  
  a new array containing length elements of array starting at offset.
- copy
  
  public static boolean[] copy(boolean[] array)
  
  Returns a copy of an array.
  
  Parameters:
  
  array - an array.
  
  Returns:
  
  a copy of array.
- fill
  
  @Deprecated public static void fill(boolean[] array, boolean value)
  
  Deprecated.
  Please use the corresponding Arrays method.
  
  Fills the given array with the given value.
  
  Parameters:
  
  array - an array.
  
  value - the new value for all elements of the array.
- fill
  
  @Deprecated public static void fill(boolean[] array, int from, int to, boolean value)
  
  Deprecated.
  Please use the corresponding Arrays method.
  
  Fills a portion of the given array with the given value.
  
  Parameters:
  
  array - an array.
  
  from - the starting index of the portion to fill (inclusive).
  
  to - the end index of the portion to fill (exclusive).
  
  value - the new value for all elements of the specified portion of the array.
- equals
  
  @Deprecated public static boolean equals(boolean[] a1, boolean[] a2)
  
  Deprecated.
  Please use the corresponding Arrays method, which is intrinsified in recent JVMs.
  
  Returns true if the two arrays are elementwise equal.
  
  Parameters:
  
  a1 - an array.
  
  a2 - another array.
  
  Returns:
  
  true if the two arrays are of the same length, and their elements are equal.
- ensureFromTo
  
  public static void ensureFromTo(boolean[] a, int from, int to)
  
  Ensures that a range given by its first (inclusive) and last (exclusive) elements fits an array.
  This method may be used whenever an array range check is needed.
  In Java 9 and up, this method should be considered deprecated in favor of the Objects.checkFromToIndex(int, int, int) method, which may be intrinsified in recent JVMs.
  
  Parameters:
  
  a - an array.
  
  from - a start index (inclusive).
  
  to - an end index (exclusive).
  
  Throws:
  
  IllegalArgumentException - if from is greater than to.
  
  ArrayIndexOutOfBoundsException - if from or to are greater than the array length or negative.
- ensureOffsetLength
  
  public static void ensureOffsetLength(boolean[] a, int offset, int length)
  
  Ensures that a range given by an offset and a length fits an array.
  This method may be used whenever an array range check is needed.
  In Java 9 and up, this method should be considered deprecated in favor of the Objects.checkFromIndexSize(int, int, int) method, which may be intrinsified in recent JVMs.
  
  Parameters:
  
  a - an array.
  
  offset - a start index.
  
  length - a length (the number of elements in the range).
  
  Throws:
  
  IllegalArgumentException - if length is negative.
  
  ArrayIndexOutOfBoundsException - if offset is negative or offset+length is greater than the array length.
- ensureSameLength
  
  public static void ensureSameLength(boolean[] a, boolean[] b)
  
  Ensures that two arrays are of the same length.
  
  Parameters:
  
  a - an array.
  
  b - another array.
  
  Throws:
  
  IllegalArgumentException - if the two argument arrays are not of the same length.
- swap
  
  public static void swap(boolean[] x, int a, int b)
  
  Swaps two elements of an anrray.
  
  Parameters:
  
  x - an array.
  
  a - a position in x.
  
  b - another position in x.
- swap
  
  public static void swap(boolean[] x, int a, int b, int n)
  
  Swaps two sequences of elements of an array.
  
  Parameters:
  
  x - an array.
  
  a - a position in x.
  
  b - another position in x.
  
  n - the number of elements to exchange starting at a and b.
- quickSort
  
  public static void quickSort(boolean[] x, int from, int to, BooleanComparator comp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
- quickSort
  
  public static void quickSort(boolean[] x, BooleanComparator comp)
  
  Sorts an array according to the order induced by the specified comparator using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  x - the array to be sorted.
  
  comp - the comparator to determine the sorting order.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x, int from, int to, BooleanComparator comp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  
  Parameters:
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x, BooleanComparator comp)
  
  Sorts an array according to the order induced by the specified comparator using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  
  Parameters:
  
  x - the array to be sorted.
  
  comp - the comparator to determine the sorting order.
- quickSort
  
  public static void quickSort(boolean[] x, int from, int to)
  
  Sorts the specified range of elements according to the natural ascending order using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- quickSort
  
  public static void quickSort(boolean[] x)
  
  Sorts an array according to the natural ascending order using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  x - the array to be sorted.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x, int from, int to)
  
  Sorts the specified range of elements according to the natural ascending order using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  
  Parameters:
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x)
  
  Sorts an array according to the natural ascending order using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  
  Parameters:
  
  x - the array to be sorted.
- quickSortIndirect
  
  public static void quickSortIndirect(int[] perm, boolean[] x, int from, int to)
  
  Sorts the specified range of elements according to the natural ascending order using indirect quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implement an indirect sort. The elements of perm (which must be exactly the numbers in the interval [0..perm.length)) will be permuted so that x[perm[i]] ≤ x[perm[i + 1]].
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  perm - a permutation array indexing x.
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- quickSortIndirect
  
  public static void quickSortIndirect(int[] perm, boolean[] x)
  
  Sorts an array according to the natural ascending order using indirect quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implement an indirect sort. The elements of perm (which must be exactly the numbers in the interval [0..perm.length)) will be permuted so that x[perm[i]] ≤ x[perm[i + 1]].
  Note that this implementation does not allocate any object, contrarily to the implementation used to sort primitive types in Arrays, which switches to mergesort on large inputs.
  
  Parameters:
  
  perm - a permutation array indexing x.
  
  x - the array to be sorted.
- parallelQuickSortIndirect
  
  public static void parallelQuickSortIndirect(int[] perm, boolean[] x, int from, int to)
  
  Sorts the specified range of elements according to the natural ascending order using a parallel indirect quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implement an indirect sort. The elements of perm (which must be exactly the numbers in the interval [0..perm.length)) will be permuted so that x[perm[i]] ≤ x[perm[i + 1]].
  
  Parameters:
  
  perm - a permutation array indexing x.
  
  x - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- parallelQuickSortIndirect
  
  public static void parallelQuickSortIndirect(int[] perm, boolean[] x)
  
  Sorts an array according to the natural ascending order using a parallel indirect quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implement an indirect sort. The elements of perm (which must be exactly the numbers in the interval [0..perm.length)) will be permuted so that x[perm[i]] ≤ x[perm[i + 1]].
  
  Parameters:
  
  perm - a permutation array indexing x.
  
  x - the array to be sorted.
- stabilize
  
  public static void stabilize(int[] perm, boolean[] x, int from, int to)
  
  Stabilizes a permutation.
  This method can be used to stabilize the permutation generated by an indirect sorting, assuming that initially the permutation array was in ascending order (e.g., the identity, as usually happens). This method scans the permutation, and for each non-singleton block of elements with the same associated values in x, permutes them in ascending order. The resulting permutation corresponds to a stable sort.
  Usually combining an unstable indirect sort and this method is more efficient than using a stable sort, as most stable sort algorithms require a support array.
  More precisely, assuming that x[perm[i]] ≤ x[perm[i + 1]], after stabilization we will also have that x[perm[i]] = x[perm[i + 1]] implies perm[i] ≤ perm[i + 1].
  
  Parameters:
  
  perm - a permutation array indexing x so that it is sorted.
  
  x - the sorted array to be stabilized.
  
  from - the index of the first element (inclusive) to be stabilized.
  
  to - the index of the last element (exclusive) to be stabilized.
- stabilize
  
  public static void stabilize(int[] perm, boolean[] x)
  
  Stabilizes a permutation.
  This method can be used to stabilize the permutation generated by an indirect sorting, assuming that initially the permutation array was in ascending order (e.g., the identity, as usually happens). This method scans the permutation, and for each non-singleton block of elements with the same associated values in x, permutes them in ascending order. The resulting permutation corresponds to a stable sort.
  Usually combining an unstable indirect sort and this method is more efficient than using a stable sort, as most stable sort algorithms require a support array.
  More precisely, assuming that x[perm[i]] ≤ x[perm[i + 1]], after stabilization we will also have that x[perm[i]] = x[perm[i + 1]] implies perm[i] ≤ perm[i + 1].
  
  Parameters:
  
  perm - a permutation array indexing x so that it is sorted.
  
  x - the sorted array to be stabilized.
- quickSort
  
  public static void quickSort(boolean[] x, boolean[] y, int from, int to)
  
  Sorts the specified range of elements of two arrays according to the natural lexicographical ascending order using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implements a lexicographical sorting of the arguments. Pairs of elements in the same position in the two provided arrays will be considered a single key, and permuted accordingly. In the end, either x[i] < x[i + 1] or x[i] == x[i + 1] and y[i] ≤ y[i + 1].
  
  Parameters:
  
  x - the first array to be sorted.
  
  y - the second array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- quickSort
  
  public static void quickSort(boolean[] x, boolean[] y)
  
  Sorts two arrays according to the natural lexicographical ascending order using quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implements a lexicographical sorting of the arguments. Pairs of elements in the same position in the two provided arrays will be considered a single key, and permuted accordingly. In the end, either x[i] < x[i + 1] or x[i] == x[i + 1] and y[i] ≤ y[i + 1].
  
  Parameters:
  
  x - the first array to be sorted.
  
  y - the second array to be sorted.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x, boolean[] y, int from, int to)
  
  Sorts the specified range of elements of two arrays according to the natural lexicographical ascending order using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implements a lexicographical sorting of the arguments. Pairs of elements in the same position in the two provided arrays will be considered a single key, and permuted accordingly. In the end, either x[i] < x[i + 1] or x[i] == x[i + 1] and y[i] ≤ y[i + 1].
  
  Parameters:
  
  x - the first array to be sorted.
  
  y - the second array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- parallelQuickSort
  
  public static void parallelQuickSort(boolean[] x, boolean[] y)
  
  Sorts two arrays according to the natural lexicographical ascending order using a parallel quicksort.
  The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
  This method implements a lexicographical sorting of the arguments. Pairs of elements in the same position in the two provided arrays will be considered a single key, and permuted accordingly. In the end, either x[i] < x[i + 1] or x[i] == x[i + 1] and y[i] ≤ y[i + 1].
  
  Parameters:
  
  x - the first array to be sorted.
  
  y - the second array to be sorted.
- unstableSort
  
  public static void unstableSort(boolean[] a, int from, int to)
  
  Sorts an array according to the natural ascending order, potentially dynamically choosing an appropriate algorithm given the type and size of the array. The sort will be stable unless it is provable that it would be impossible for there to be any difference between a stable and unstable sort for the given type, in which case stability is meaningless and thus unspecified.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  Since:
  
  8.3.0
- unstableSort
  
  public static void unstableSort(boolean[] a)
  
  Sorts the specified range of elements according to the natural ascending order potentially dynamically choosing an appropriate algorithm given the type and size of the array. No assurance is made of the stability of the sort.
  
  Parameters:
  
  a - the array to be sorted.
  
  Since:
  
  8.3.0
- unstableSort
  
  public static void unstableSort(boolean[] a, int from, int to, BooleanComparator comp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array. No assurance is made of the stability of the sort.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
  
  Since:
  
  8.3.0
- unstableSort
  
  public static void unstableSort(boolean[] a, BooleanComparator comp)
  
  Sorts an array according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array. No assurance is made of the stability of the sort.
  
  Parameters:
  
  a - the array to be sorted.
  
  comp - the comparator to determine the sorting order.
  
  Since:
  
  8.3.0
- mergeSort
  
  public static void mergeSort(boolean[] a, int from, int to, boolean[] supp)
  
  Sorts the specified range of elements according to the natural ascending order using mergesort, using a given pre-filled support array.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. Moreover, no support arrays will be allocated.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  supp - a support array containing at least to elements, and whose entries are identical to those of a in the specified range. It can be null, in which case a will be cloned.
- mergeSort
  
  public static void mergeSort(boolean[] a, int from, int to)
  
  Sorts the specified range of elements according to the natural ascending order using mergesort.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. An array as large as a will be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
- mergeSort
  
  public static void mergeSort(boolean[] a)
  
  Sorts an array according to the natural ascending order using mergesort.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. An array as large as a will be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
- mergeSort
  
  public static void mergeSort(boolean[] a, int from, int to, BooleanComparator comp, boolean[] supp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator using mergesort, using a given pre-filled support array.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. Moreover, no support arrays will be allocated.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
  
  supp - a support array containing at least to elements, and whose entries are identical to those of a in the specified range. It can be null, in which case a will be cloned.
- mergeSort
  
  public static void mergeSort(boolean[] a, int from, int to, BooleanComparator comp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator using mergesort.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. An array as large as a will be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
- mergeSort
  
  public static void mergeSort(boolean[] a, BooleanComparator comp)
  
  Sorts an array according to the order induced by the specified comparator using mergesort.
  This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. An array as large as a will be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  comp - the comparator to determine the sorting order.
- stableSort
  
  public static void stableSort(boolean[] a, int from, int to)
  
  Sorts an array according to the natural ascending order, potentially dynamically choosing an appropriate algorithm given the type and size of the array. The sort will be stable unless it is provable that it would be impossible for there to be any difference between a stable and unstable sort for the given type, in which case stability is meaningless and thus unspecified.
  An array as large as a may be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  Since:
  
  8.3.0
- stableSort
  
  public static void stableSort(boolean[] a)
  
  Sorts the specified range of elements according to the natural ascending order potentially dynamically choosing an appropriate algorithm given the type and size of the array. The sort will be stable unless it is provable that it would be impossible for there to be any difference between a stable and unstable sort for the given type, in which case stability is meaningless and thus unspecified.
  An array as large as a may be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  Since:
  
  8.3.0
- stableSort
  
  public static void stableSort(boolean[] a, int from, int to, BooleanComparator comp)
  
  Sorts the specified range of elements according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array. The sort will be stable unless it is provable that it would be impossible for there to be any difference between a stable and unstable sort for the given type, in which case stability is meaningless and thus unspecified.
  An array as large as a may be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  from - the index of the first element (inclusive) to be sorted.
  
  to - the index of the last element (exclusive) to be sorted.
  
  comp - the comparator to determine the sorting order.
  
  Since:
  
  8.3.0
- stableSort
  
  public static void stableSort(boolean[] a, BooleanComparator comp)
  
  Sorts an array according to the order induced by the specified comparator, potentially dynamically choosing an appropriate algorithm given the type and size of the array. The sort will be stable unless it is provable that it would be impossible for there to be any difference between a stable and unstable sort for the given type, in which case stability is meaningless and thus unspecified.
  An array as large as a may be allocated by this method.
  
  Parameters:
  
  a - the array to be sorted.
  
  comp - the comparator to determine the sorting order.
  
  Since:
  
  8.3.0
- shuffle
  
  public static boolean[] shuffle(boolean[] a, int from, int to, Random random)
  
  Shuffles the specified array fragment using the specified pseudorandom number generator.
  
  Parameters:
  
  a - the array to be shuffled.
  
  from - the index of the first element (inclusive) to be shuffled.
  
  to - the index of the last element (exclusive) to be shuffled.
  
  random - a pseudorandom number generator.
  
  Returns:
  
  a.
- shuffle
  
  public static boolean[] shuffle(boolean[] a, Random random)
  
  Shuffles the specified array using the specified pseudorandom number generator.
  
  Parameters:
  
  a - the array to be shuffled.
  
  random - a pseudorandom number generator.
  
  Returns:
  
  a.
- reverse
  
  public static boolean[] reverse(boolean[] a)
  
  Reverses the order of the elements in the specified array.
  
  Parameters:
  
  a - the array to be reversed.
  
  Returns:
  
  a.
- reverse
  
  public static boolean[] reverse(boolean[] a, int from, int to)
  
  Reverses the order of the elements in the specified array fragment.
  
  Parameters:
  
  a - the array to be reversed.
  
  from - the index of the first element (inclusive) to be reversed.
  
  to - the index of the last element (exclusive) to be reversed.
  
  Returns:
  
  a.

Class BooleanArrays

Sorting

Parallel operations

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

EMPTY_ARRAY

DEFAULT_EMPTY_ARRAY

HASH_STRATEGY

Method Details

forceCapacity

ensureCapacity

ensureCapacity

grow

grow

trim

setLength

copy

copy

fill

fill

equals

ensureFromTo

ensureOffsetLength

ensureSameLength

swap

swap

quickSort

quickSort

parallelQuickSort

parallelQuickSort

quickSort

quickSort

parallelQuickSort

parallelQuickSort

quickSortIndirect

quickSortIndirect

parallelQuickSortIndirect

parallelQuickSortIndirect

stabilize

stabilize

quickSort

quickSort

parallelQuickSort

parallelQuickSort

unstableSort

unstableSort

unstableSort

unstableSort

mergeSort

mergeSort

mergeSort

mergeSort

mergeSort

mergeSort

stableSort

stableSort

stableSort

stableSort

shuffle

shuffle

reverse

reverse