# Quick Sort Implementation with median-of-three partitioning and cutoff for small arrays : Sort Search « Collections Data Structure « Java

Quick Sort Implementation with median-of-three partitioning and cutoff for small arrays

```

public class Main {
public static void main(String args[]) {
}

public static void quicksort(Comparable[] a) {
quicksort(a, 0, a.length - 1);
}

static void quicksort(Comparable[] a, int low, int high) {
int CUTOFF = 10;
if (low + CUTOFF > high)
insertionSort(a, low, high);
else {
int middle = (low + high) / 2;
if (a[middle].compareTo(a[low]) < 0)
swapReferences(a, low, middle);
if (a[high].compareTo(a[low]) < 0)
swapReferences(a, low, high);
if (a[high].compareTo(a[middle]) < 0)
swapReferences(a, middle, high);

swapReferences(a, middle, high - 1);
Comparable pivot = a[high - 1];

int i, j;
for (i = low, j = high - 1;;) {
while (a[++i].compareTo(pivot) < 0)
;
while (pivot.compareTo(a[--j]) < 0)
;
if (i >= j)
break;
swapReferences(a, i, j);
}
swapReferences(a, i, high - 1);

quicksort(a, low, i - 1);
quicksort(a, i + 1, high);
}
}

public static final void swapReferences(Object[] a, int index1, int index2) {
Object tmp = a[index1];
a[index1] = a[index2];
a[index2] = tmp;
}

private static void insertionSort(Comparable[] a, int low, int high) {
for (int p = low + 1; p <= high; p++) {
Comparable tmp = a[p];
int j;

for (j = p; j > low && tmp.compareTo(a[j - 1]) < 0; j--)
a[j] = a[j - 1];
a[j] = tmp;
}
}
}

```

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