Simple version of quick sort : Sort Search « Collections Data Structure « Java
Simple version of quick sort
public class QuickSortSimpleVersion {
private long[] data;
private int len;
public QuickSortSimpleVersion(int max) {
data = new long[max];
len = 0;
}
public void insert(long value) {
data[len] = value;
len++;
}
public void display() {
System.out.print("Data");
for (int j = 0; j < len; j++)
System.out.print(data[j] + " ");
System.out.println("");
}
public void quickSort() {
recQuickSort(0, len - 1);
}
public void recQuickSort(int left, int right) {
if (right - left <= 0) // if size <= 1 already sorted
return;
else // size is 2 or larger
{
long pivot = data[right]; // rightmost item
// partition range
int partition = partitionData(left, right, pivot);
recQuickSort(left, partition - 1); // sort left side
recQuickSort(partition + 1, right); // sort right side
}
}
public int partitionData(int left, int right, long pivot) {
int leftPtr = left - 1; // left (after ++)
int rightPtr = right; // right-1 (after --)
while (true) { // find bigger item
while (data[++leftPtr] < pivot)
;
// find smaller item
while (rightPtr > 0 && data[--rightPtr] > pivot)
;
if (leftPtr >= rightPtr) // if pointers cross, partition done
break;
else
swap(leftPtr, rightPtr);
}
swap(leftPtr, right); // restore pivot and return pivot location
return leftPtr;
}
public void swap(int d1, int d2) {
long temp = data[d1];
data[d1] = data[d2];
data[d2] = temp;
}
public static void main(String[] args) {
int maxSize = 16; // array size
QuickSortSimpleVersion arr = new QuickSortSimpleVersion(maxSize); // create array
for (int j = 0; j < maxSize; j++) // fill array with random numbers
{
long n = (int) (java.lang.Math.random() * 99);
arr.insert(n);
}
arr.display();
arr.quickSort();
arr.display();
}
}
