it.unimi.dsi.fastutil.booleans.BooleanBigArrays Maven / Gradle / Ivy
/*
* Copyright (C) 2009-2017 Sebastiano Vigna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*
*
* Copyright (C) 1999 CERN - European Organization for Nuclear Research.
*
* Permission to use, copy, modify, distribute and sell this software and
* its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation. CERN makes no representations about the
* suitability of this software for any purpose. It is provided "as is"
* without expressed or implied warranty.
*/
package it.unimi.dsi.fastutil.booleans;
import java.util.Arrays;
import java.util.Random;
import it.unimi.dsi.fastutil.BigArrays;
import it.unimi.dsi.fastutil.Hash;
import static it.unimi.dsi.fastutil.BigArrays.ensureLength;
import static it.unimi.dsi.fastutil.BigArrays.start;
import static it.unimi.dsi.fastutil.BigArrays.segment;
import static it.unimi.dsi.fastutil.BigArrays.displacement;
import static it.unimi.dsi.fastutil.BigArrays.SEGMENT_MASK;
import static it.unimi.dsi.fastutil.BigArrays.SEGMENT_SHIFT;
import static it.unimi.dsi.fastutil.BigArrays.SEGMENT_SIZE;
/** A class providing static methods and objects that do useful things with {@linkplain BigArrays big arrays}.
*
* In particular, the ensureCapacity(), grow(),
* trim() and setLength() methods allow to handle
* big arrays much like array lists.
*
*
Note that {@link it.unimi.dsi.fastutil.io.BinIO} and {@link it.unimi.dsi.fastutil.io.TextIO}
* contain several methods that make it possible to load and save big arrays of primitive types as sequences
* of elements in {@link java.io.DataInput} format (i.e., not as objects) or as sequences of lines of text.
*
* @see BigArrays
*/
public class BooleanBigArrays {
private BooleanBigArrays() {}
/** A static, final, empty big array. */
public final static boolean[][] EMPTY_BIG_ARRAY = {};
/** Returns the element of the given big array of specified index.
*
* @param array a big array.
* @param index a position in the big array.
* @return the element of the big array at the specified position.
*/
public static boolean get(final boolean[][] array, final long index) {
return array[segment(index)][displacement(index)];
}
/** Sets the element of the given big array of specified index.
*
* @param array a big array.
* @param index a position in the big array.
* @param value the new value for the array element at the specified position.
*/
public static void set(final boolean[][] array, final long index, boolean value) {
array[segment(index)][displacement(index)] = value;
}
/** Swaps the element of the given big array of specified indices.
*
* @param array a big array.
* @param first a position in the big array.
* @param second a position in the big array.
*/
public static void swap(final boolean[][] array, final long first, final long second) {
final boolean t = array[segment(first)][displacement(first)];
array[segment(first)][displacement(first)] = array[segment(second)][displacement(second)];
array[segment(second)][displacement(second)] = t;
}
/** Returns the length of the given big array.
*
* @param array a big array.
* @return the length of the given big array.
*/
public static long length(final boolean[][] array) {
final int length = array.length;
return length == 0 ? 0 : start(length - 1) + array[length - 1].length;
}
/** Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination big array.
* Handles correctly overlapping regions of the same big array.
*
* @param srcArray the source big array.
* @param srcPos the starting position in the source big array.
* @param destArray the destination big array.
* @param destPos the starting position in the destination data.
* @param length the number of elements to be copied.
*/
public static void copy(final boolean[][] srcArray, final long srcPos, final boolean[][] destArray, final long destPos, long length) {
if (destPos <= srcPos) {
int srcSegment = segment(srcPos);
int destSegment = segment(destPos);
int srcDispl = displacement(srcPos);
int destDispl = displacement(destPos);
int l;
while(length > 0) {
l = (int)Math.min(length, Math.min(srcArray[srcSegment].length - srcDispl, destArray[destSegment].length - destDispl));
System.arraycopy(srcArray[srcSegment], srcDispl, destArray[destSegment], destDispl, l);
if ((srcDispl += l) == SEGMENT_SIZE) {
srcDispl = 0;
srcSegment++;
}
if ((destDispl += l) == SEGMENT_SIZE) {
destDispl = 0;
destSegment++;
}
length -= l;
}
}
else {
int srcSegment = segment(srcPos + length);
int destSegment = segment(destPos + length);
int srcDispl = displacement(srcPos + length);
int destDispl = displacement(destPos + length);
int l;
while(length > 0) {
if (srcDispl == 0) {
srcDispl = SEGMENT_SIZE;
srcSegment--;
}
if (destDispl == 0) {
destDispl = SEGMENT_SIZE;
destSegment--;
}
l = (int)Math.min(length, Math.min(srcDispl, destDispl));
System.arraycopy(srcArray[srcSegment], srcDispl - l, destArray[destSegment], destDispl - l, l);
srcDispl -= l;
destDispl -= l;
length -= l;
}
}
}
/** Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination array.
*
* @param srcArray the source big array.
* @param srcPos the starting position in the source big array.
* @param destArray the destination array.
* @param destPos the starting position in the destination data.
* @param length the number of elements to be copied.
*/
public static void copyFromBig(final boolean[][] srcArray, final long srcPos, final boolean[] destArray, int destPos, int length) {
int srcSegment = segment(srcPos);
int srcDispl = displacement(srcPos);
int l;
while(length > 0) {
l = Math.min(srcArray[srcSegment].length - srcDispl, length);
System.arraycopy(srcArray[srcSegment], srcDispl, destArray, destPos, l);
if ((srcDispl += l) == SEGMENT_SIZE) {
srcDispl = 0;
srcSegment++;
}
destPos += l;
length -= l;
}
}
/** Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination big array.
*
* @param srcArray the source array.
* @param srcPos the starting position in the source array.
* @param destArray the destination big array.
* @param destPos the starting position in the destination data.
* @param length the number of elements to be copied.
*/
public static void copyToBig(final boolean[] srcArray, int srcPos, final boolean[][] destArray, final long destPos, long length) {
int destSegment = segment(destPos);
int destDispl = displacement(destPos);
int l;
while(length > 0) {
l = (int)Math.min(destArray[destSegment].length - destDispl, length);
System.arraycopy(srcArray, srcPos, destArray[destSegment], destDispl, l);
if ((destDispl += l) == SEGMENT_SIZE) {
destDispl = 0;
destSegment++;
}
srcPos += l;
length -= l;
}
}
/** Creates a new big array.
*
* @param length the length of the new big array.
* @return a new big array of given length.
*/
public static boolean[][] newBigArray(final long length) {
if (length == 0) return EMPTY_BIG_ARRAY;
ensureLength(length);
final int baseLength = (int)((length + SEGMENT_MASK) >>> SEGMENT_SHIFT);
boolean[][] base = new boolean[baseLength][];
final int residual = (int)(length & SEGMENT_MASK);
if (residual != 0) {
for(int i = 0; i < baseLength - 1; i++) base[i] = new boolean[SEGMENT_SIZE];
base[baseLength - 1] = new boolean[residual];
}
else for(int i = 0; i < baseLength; i++) base[i] = new boolean[SEGMENT_SIZE];
return base;
}
/** Turns a standard array into a big array.
*
*
Note that the returned big array might contain as a segment the original array.
*
* @param array an array.
* @return a new big array with the same length and content of array.
*/
public static boolean[][] wrap(final boolean[] array) {
if (array.length == 0) return EMPTY_BIG_ARRAY;
if (array.length <= SEGMENT_SIZE) return new boolean[][] { array };
final boolean[][] bigArray = newBigArray(array.length);
for(int i = 0; i < bigArray.length; i++) System.arraycopy(array, (int)start(i), bigArray[i], 0, bigArray[i].length);
return bigArray;
}
/** Ensures that a big array can contain the given number of entries.
*
*
If you cannot foresee whether this big array will need again to be
* enlarged, you should probably use grow() instead.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new minimum length for this big array.
* @return array, if it contains length entries or more; otherwise,
* a big array with length entries whose first length(array)
* entries are the same as those of array.
*/
public static boolean[][] ensureCapacity(final boolean[][] array, final long length) {
return ensureCapacity(array, length, length(array));
}
/** Ensures that a big array can contain the given number of entries, preserving just a part of the big array.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new minimum length for this big array.
* @param preserve the number of elements of the big array that must be preserved in case a new allocation is necessary.
* @return array, if it can contain length entries or more; otherwise,
* a big array with length entries whose first preserve
* entries are the same as those of array.
*/
public static boolean[][] ensureCapacity(final boolean[][] array, final long length, final long preserve) {
final long oldLength = length(array);
if (length > oldLength) {
ensureLength(length);
final int valid = array.length - (array.length == 0 || array.length > 0 && array[array.length - 1].length == SEGMENT_SIZE ? 0 : 1);
final int baseLength = (int)((length + SEGMENT_MASK) >>> SEGMENT_SHIFT);
final boolean[][] base = Arrays.copyOf(array, baseLength);
final int residual = (int)(length & SEGMENT_MASK);
if (residual != 0) {
for(int i = valid; i < baseLength - 1; i++) base[i] = new boolean[SEGMENT_SIZE];
base[baseLength - 1] = new boolean[residual];
}
else for(int i = valid; i < baseLength; i++) base[i] = new boolean[SEGMENT_SIZE];
if (preserve - (valid * (long)SEGMENT_SIZE) > 0) copy(array, valid * (long)SEGMENT_SIZE, base, valid * (long)SEGMENT_SIZE, preserve - (valid * (long)SEGMENT_SIZE));
return base;
}
return array;
}
/** Grows the given big array to the maximum between the given length and
* the current length multiplied by two, provided that the given
* length is larger than the current length.
*
*
If you want complete control on the big array growth, you
* should probably use ensureCapacity() instead.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new minimum length for this big array.
* @return array, if it can contain length
* entries; otherwise, a big array with
* max(length,length(array)/φ) entries whose first
* length(array) entries are the same as those of array.
* */
public static boolean[][] grow(final boolean[][] array, final long length) {
final long oldLength = length(array);
return length > oldLength ? grow(array, length, oldLength) : array;
}
/** Grows the given big array to the maximum between the given length and
* the current length multiplied by two, provided that the given
* length is larger than the current length, preserving just a part of the big array.
*
*
If you want complete control on the big array growth, you
* should probably use ensureCapacity() instead.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new minimum length for this big array.
* @param preserve the number of elements of the big array that must be preserved in case a new allocation is necessary.
* @return array, if it can contain length
* entries; otherwise, a big array with
* max(length,length(array)/φ) entries whose first
* preserve entries are the same as those of array.
* */
public static boolean[][] grow(final boolean[][] array, final long length, final long preserve) {
final long oldLength = length(array);
return length > oldLength ? ensureCapacity(array, Math.max(2 * oldLength, length), preserve) : array;
}
/** Trims the given big array to the given length.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new maximum length for the big array.
* @return array, if it contains length
* entries or less; otherwise, a big array with
* length entries whose entries are the same as
* the first length entries of array.
*
*/
public static boolean[][] trim(final boolean[][] array, final long length) {
ensureLength(length);
final long oldLength = length(array);
if (length >= oldLength) return array;
final int baseLength = (int)((length + SEGMENT_MASK) >>> SEGMENT_SHIFT);
final boolean[][] base = Arrays.copyOf(array, baseLength);
final int residual = (int)(length & SEGMENT_MASK);
if (residual != 0) base[baseLength - 1] = BooleanArrays.trim(base[baseLength - 1], residual);
return base;
}
/** Sets the length of the given big array.
*
*
Warning: the returned array might use part of the segments of the original
* array, which must be considered read-only after calling this method.
*
* @param array a big array.
* @param length the new length for the big array.
* @return array, if it contains exactly length
* entries; otherwise, if it contains more than
* length entries, a big array with length entries
* whose entries are the same as the first length entries of
* array; otherwise, a big array with length entries
* whose first length(array) entries are the same as those of
* array.
*
*/
public static boolean[][] setLength(final boolean[][] array, final long length) {
final long oldLength = length(array);
if (length == oldLength) return array;
if (length < oldLength) return trim(array, length);
return ensureCapacity(array, length);
}
/** Returns a copy of a portion of a big array.
*
* @param array a big array.
* @param offset the first element to copy.
* @param length the number of elements to copy.
* @return a new big array containing length elements of array starting at offset.
*/
public static boolean[][] copy(final boolean[][] array, final long offset, final long length) {
ensureOffsetLength(array, offset, length);
final boolean[][] a =
newBigArray(length);
copy(array, offset, a, 0, length);
return a;
}
/** Returns a copy of a big array.
*
* @param array a big array.
* @return a copy of array.
*/
public static boolean[][] copy(final boolean[][] array) {
final boolean[][] base = array.clone();
for(int i = base.length; i-- != 0;) base[i] = array[i].clone();
return base;
}
/** Fills the given big array with the given value.
*
*
This method uses a backward loop. It is significantly faster than the corresponding
* method in {@link java.util.Arrays}.
*
* @param array a big array.
* @param value the new value for all elements of the big array.
*/
public static void fill(final boolean[][] array, final boolean value) {
for(int i = array.length; i-- != 0;) Arrays.fill(array[i], value);
}
/** Fills a portion of the given big array with the given value.
*
*
If possible (i.e., from is 0) this method uses a
* backward loop. In this case, it is significantly faster than the
* corresponding method in {@link java.util.Arrays}.
*
* @param array a big array.
* @param from the starting index of the portion to fill.
* @param to the end index of the portion to fill.
* @param value the new value for all elements of the specified portion of the big array.
*/
public static void fill(final boolean[][] array, final long from, long to, final boolean value) {
final long length = length(array);
BigArrays.ensureFromTo(length, from, to);
int fromSegment = segment(from);
int toSegment = segment(to);
int fromDispl = displacement(from);
int toDispl = displacement(to);
if (fromSegment == toSegment) {
Arrays.fill(array[fromSegment], fromDispl, toDispl, value);
return;
}
if (toDispl != 0) Arrays.fill(array[toSegment], 0, toDispl, value);
while(--toSegment > fromSegment) Arrays.fill(array[toSegment], value);
Arrays.fill(array[fromSegment], fromDispl, SEGMENT_SIZE, value);
}
/** Returns true if the two big arrays are elementwise equal.
*
*
This method uses a backward loop. It is significantly faster than the corresponding
* method in {@link java.util.Arrays}.
*
* @param a1 a big array.
* @param a2 another big array.
* @return true if the two big arrays are of the same length, and their elements are equal.
*/
public static boolean equals(final boolean[][] a1, final boolean a2[][]) {
if (length(a1) != length(a2)) return false;
int i = a1.length, j;
boolean[] t, u;
while(i-- != 0) {
t = a1[i];
u = a2[i];
j = t.length;
while(j-- != 0) if (! ( (t[j]) == (u[j]) )) return false;
}
return true;
}
/* Returns a string representation of the contents of the specified big array.
*
* The string representation consists of a list of the big array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns "null" if a is null.
* @param a the big array whose string representation to return.
* @return the string representation of a.
*/
public static String toString(final boolean[][] a) {
if (a == null) return "null";
final long last = length(a) - 1;
if (last == - 1) return "[]";
final StringBuilder b = new StringBuilder();
b.append('[');
for (long i = 0; ; i++) {
b.append(String.valueOf(get(a, i)));
if (i == last) return b.append(']').toString();
b.append(", ");
}
}
/** Ensures that a range given by its first (inclusive) and last (exclusive) elements fits a big array.
*
*
This method may be used whenever a big array range check is needed.
*
* @param a a big array.
* @param from a start index (inclusive).
* @param to an end index (inclusive).
* @throws IllegalArgumentException if from is greater than to.
* @throws ArrayIndexOutOfBoundsException if from or to are greater than the big array length or negative.
*/
public static void ensureFromTo(final boolean[][] a, final long from, final long to) {
BigArrays.ensureFromTo(length(a), from, to);
}
/** Ensures that a range given by an offset and a length fits a big array.
*
*
This method may be used whenever a big array range check is needed.
*
* @param a a big array.
* @param offset a start index.
* @param length a length (the number of elements in the range).
* @throws IllegalArgumentException if length is negative.
* @throws ArrayIndexOutOfBoundsException if offset is negative or offset+length is greater than the big array length.
*/
public static void ensureOffsetLength(final boolean[][] a, final long offset, final long length) {
BigArrays.ensureOffsetLength(length(a), offset, length);
}
/** A type-specific content-based hash strategy for big arrays. */
private static final class BigArrayHashStrategy implements Hash.Strategy, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
public int hashCode(final boolean[][] o) {
return java.util.Arrays.deepHashCode(o);
}
public boolean equals(final boolean[][] a, final boolean[][] b) {
return BooleanBigArrays.equals(a, b);
}
}
/** A type-specific content-based hash strategy for big arrays.
*
* This hash strategy may be used in custom hash collections whenever keys are
* big arrays, and they must be considered equal by content. This strategy
* will handle {@code null} correctly, and it is serializable.
*/
@SuppressWarnings({"rawtypes"})
public final static Hash.Strategy HASH_STRATEGY = new BigArrayHashStrategy();
private static final int SMALL = 7;
private static final int MEDIUM = 40;
private static void vecSwap(final boolean[][] x, long a, long b, final long n) {
for(int i = 0; i < n; i++, a++, b++) swap(x, a, b);
}
private static long med3(final boolean x[][], final long a, final long b, final long c, BooleanComparator comp) {
int ab = comp.compare(get(x, a), get(x, b));
int ac = comp.compare(get(x, a), get(x, c));
int bc = comp.compare(get(x, b), get(x, c));
return (ab < 0 ?
(bc < 0 ? b : ac < 0 ? c : a) :
(bc > 0 ? b : ac > 0 ? c : a));
}
private static void selectionSort(final boolean[][] a, final long from, final long to, final BooleanComparator comp) {
for(long i = from; i < to - 1; i++) {
long m = i;
for(long j = i + 1; j < to; j++) if (comp.compare(BooleanBigArrays.get(a, j), BooleanBigArrays.get(a, m)) < 0) m = j;
if (m != i) swap(a, i, m);
}
}
/** 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.
*
* @param x the big array to be sorted.
* @param from the index of the first element (inclusive) to be sorted.
* @param to the index of the last element (exclusive) to be sorted.
* @param comp the comparator to determine the sorting order.
*/
public static void quickSort(final boolean[][] x, final long from, final long to, final BooleanComparator comp) {
final long len = to - from;
// Selection sort on smallest arrays
if (len < SMALL) {
selectionSort(x, from, to, comp);
return;
}
// Choose a partition element, v
long m = from + len / 2; // Small arrays, middle element
if (len > SMALL) {
long l = from;
long n = to - 1;
if (len > MEDIUM) { // Big arrays, pseudomedian of 9
long s = len / 8;
l = med3(x, l, l + s, l + 2 * s, comp);
m = med3(x, m - s, m, m + s, comp);
n = med3(x, n - 2 * s, n - s, n, comp);
}
m = med3(x, l, m, n, comp); // Mid-size, med of 3
}
final boolean v = get(x, m);
// Establish Invariant: v* (v)* v*
long a = from, b = a, c = to - 1, d = c;
while(true) {
int comparison;
while (b <= c && (comparison = comp.compare(get(x, b), v)) <= 0) {
if (comparison == 0) swap(x, a++, b);
b++;
}
while (c >= b && (comparison = comp.compare(get(x, c), v)) >=0) {
if (comparison == 0) swap(x, c, d--);
c--;
}
if (b > c) break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
long s, n = to;
s = Math.min(a - from, b - a);
vecSwap(x, from, b - s, s);
s = Math.min(d - c, n - d- 1);
vecSwap(x, b, n - s, s);
// Recursively sort non-partition-elements
if ((s = b - a) > 1) quickSort(x, from, from + s, comp);
if ((s = d - c) > 1) quickSort(x, n - s, n, comp);
}
private static long med3(final boolean x[][], final long a, final long b, final long c) {
int ab = ( Boolean.compare((get(x, a)),(get(x, b))) );
int ac = ( Boolean.compare((get(x, a)),(get(x, c))) );
int bc = ( Boolean.compare((get(x, b)),(get(x, c))) );
return (ab < 0 ?
(bc < 0 ? b : ac < 0 ? c : a) :
(bc > 0 ? b : ac > 0 ? c : a));
}
private static void selectionSort(final boolean[][] a, final long from, final long to) {
for(long i = from; i < to - 1; i++) {
long m = i;
for(long j = i + 1; j < to; j++) if (( !(BooleanBigArrays.get(a, j)) && (BooleanBigArrays.get(a, m)) )) m = j;
if (m != i) swap(a, i, m);
}
}
/** Sorts the specified big 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.
*
* @param x the big array to be sorted.
* @param comp the comparator to determine the sorting order.
*
*/
public static void quickSort(final boolean[][] x, final BooleanComparator comp) {
quickSort(x, 0, BooleanBigArrays.length(x), comp);
}
/** 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.
*
* @param x the big array to be sorted.
* @param from the index of the first element (inclusive) to be sorted.
* @param to the index of the last element (exclusive) to be sorted.
*/
public static void quickSort(final boolean[][] x, final long from, final long to) {
final long len = to - from;
// Selection sort on smallest arrays
if (len < SMALL) {
selectionSort(x, from, to);
return;
}
// Choose a partition element, v
long m = from + len / 2; // Small arrays, middle element
if (len > SMALL) {
long l = from;
long n = to - 1;
if (len > MEDIUM) { // Big arrays, pseudomedian of 9
long s = len / 8;
l = med3(x, l, l + s, l + 2 * s);
m = med3(x, m - s, m, m + s);
n = med3(x, n - 2 * s, n - s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
final boolean v = get(x, m);
// Establish Invariant: v* (v)* v*
long a = from, b = a, c = to - 1, d = c;
while(true) {
int comparison;
while (b <= c && (comparison = ( Boolean.compare((get(x, b)),(v)) )) <= 0) {
if (comparison == 0) swap(x, a++, b);
b++;
}
while (c >= b && (comparison = ( Boolean.compare((get(x, c)),(v)) )) >=0) {
if (comparison == 0) swap(x, c, d--);
c--;
}
if (b > c) break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
long s, n = to;
s = Math.min(a - from, b - a);
vecSwap(x, from, b - s, s);
s = Math.min(d - c, n - d- 1);
vecSwap(x, b, n - s, s);
// Recursively sort non-partition-elements
if ((s = b - a) > 1) quickSort(x, from, from + s);
if ((s = d - c) > 1) quickSort(x, n - s, n);
}
/** Sorts the specified big 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.
*
* @param x the big array to be sorted.
*/
public static void quickSort(final boolean[][] x) {
quickSort(x, 0, BooleanBigArrays.length(x));
}
/** Shuffles the specified big array fragment using the specified pseudorandom number generator.
*
* @param a the big array to be shuffled.
* @param from the index of the first element (inclusive) to be shuffled.
* @param to the index of the last element (exclusive) to be shuffled.
* @param random a pseudorandom number generator (please use a XorShift* generator).
* @return a.
*/
public static boolean[][] shuffle(final boolean[][] a, final long from, final long to, final Random random) {
for(long i = to - from; i-- != 0;) {
final long p = (random.nextLong() & 0x7FFFFFFFFFFFFFFFL) % (i + 1);
final boolean t = get(a, from + i);
set(a, from + i, get(a, from + p));
set(a, from + p, t);
}
return a;
}
/** Shuffles the specified big array using the specified pseudorandom number generator.
*
* @param a the big array to be shuffled.
* @param random a pseudorandom number generator (please use a XorShift* generator).
* @return a.
*/
public static boolean[][] shuffle(final boolean[][] a, final Random random) {
for(long i = length(a); i-- != 0;) {
final long p = (random.nextLong() & 0x7FFFFFFFFFFFFFFFL) % (i + 1);
final boolean t = get(a, i);
set(a, i, get(a, p));
set(a, p, t);
}
return a;
}
}