# Fast Quick Sort : Sort Search « Collections Data Structure « Java

Fast Quick Sort

```

import java.util.Comparator;

/**
* Maybe the fastest implementation of famous Quick-Sort
* algorithm. It is even faster than Denisa Ahrensa implementation that
* performs 7.5s for sorting million objects, this implementation
* sorts for 6.8s. However, {@link FastMergeSort} is much faster.
*/
public class FastQuickSort  {

@SuppressWarnings({"unchecked"})
public static void qsort(Object[] c, Comparator comparator) {
int i, j, left = 0, right = c.length - 1, stack_pointer = -1;
int[] stack = new int[128];
Object swap, temp;
while (true) {
if (right - left <= 7) {
for (j = left + 1; j <= right; j++) {
swap = c[j];
i = j - 1;
while (i >= left && comparator.compare(c[i], swap) > 0) {
c[i + 1] = c[i--];
}
c[i + 1] = swap;
}
if (stack_pointer == -1) {
break;
}
right = stack[stack_pointer--];
left = stack[stack_pointer--];
} else {
int median = (left + right) >> 1;
i = left + 1;
j = right;
swap = c[median]; c[median] = c[i]; c[i] = swap;
if (comparator.compare(c[left], c[right]) > 0) {
swap = c[left]; c[left] = c[right]; c[right] = swap;
}
if (comparator.compare(c[i], c[right]) > 0) {
swap = c[i]; c[i] = c[right]; c[right] = swap;
}
if (comparator.compare(c[left], c[i]) > 0) {
swap = c[left]; c[left] = c[i]; c[i] = swap;
}
temp = c[i];
while (true) {
//noinspection ControlFlowStatementWithoutBraces,StatementWithEmptyBody
while (comparator.compare(c[++i], temp) < 0);
//noinspection ControlFlowStatementWithoutBraces,StatementWithEmptyBody
while (comparator.compare(c[--j], temp) > 0);
if (j < i) {
break;
}
swap = c[i]; c[i] = c[j]; c[j] = swap;
}
c[left + 1] = c[j];
c[j] = temp;
if (right - i + 1 >= j - left) {
stack[++stack_pointer] = i;
stack[++stack_pointer] = right;
right = j - 1;
} else {
stack[++stack_pointer] = left;
stack[++stack_pointer] = j - 1;
left = i;
}
}
}
}

public void sort(Object a[], Comparator comparator) {
qsort(a, comparator);
}

public void sort(Comparable a[]) {
qsort(a, new ComparableComparator());
}

// ---------------------------------------------------------------- static

public static void doSort(Object a[], Comparator comparator) {
qsort(a, comparator);
}

public static void doSort(Comparable a[]) {
qsort(a, ComparableComparator.INSTANCE);
}

}

/**
* Comparator that adapts <code>Comparables</code> to the
* <code>Comparator</code> interface.
*/
class ComparableComparator<T extends Comparable<T>> implements Comparator<T> {

/**
* Cached instance.
*/
public static final ComparableComparator INSTANCE = new ComparableComparator();

public int compare(T o1, T o2) {
return o1.compareTo(o2);
}

}

```

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 1 Linear search 2 Animation for quick sort 3 Quick Sort Implementation with median-of-three partitioning and cutoff for small arrays 4 Simple Sort Demo 5 A simple applet class to demonstrate a sort algorithm 6 Sorting an array of Strings 7 Simple version of quick sort 8 Combine Quick Sort Insertion Sort 9 Quick sort with median-of-three partitioning 10 Selection sort 11 Insert Sort for objects 12 Insert sort 13 Bubble sort 14 Merge sort 15 Fast Merge Sort 16 Binary Search 17 Shell sort 18 Recursive Binary Search Implementation in Java 19 Topological sorting 20 Heap sort 21 Sort Numbers 22 A quick sort demonstration algorithm 23 Performing Binary Search on Java byte Array Example 24 Performing Binary Search on Java char Array Example 25 Performing Binary Search on Java double Array Example 26 Performing Binary Search on Java float Array Example 27 Performing Binary Search on Java int Array Example 28 Performing Binary Search on Java long Array Example 29 Performing Binary Search on Java short Array 30 Sort items of an array 31 Sort an array of objects 32 Sort a String array 33 Sort string array with Collator 34 Binary search routines 35 FastQ Sorts the [l,r] partition (inclusive) of the specfied array of Rows, using the comparator. 36 A binary search implementation. 37 Handles QuickSort and all of its methods. 38 Implements QuickSort three different ways 39 A quick sort algorithm to sort Vectors or arrays. Provides sort and binary search capabilities. 40 Returns an array of indices indicating the order the data should be sorted in.