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Merged
christianbender merged 1 commit into from
Mar 30, 2018
Merged

QuickSortAlgo.java #397

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76 changes: 45 additions & 31 deletions Sorts/QuickSort.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,11 +15,13 @@ class QuickSort {
* Sorts the array in increasing order
**/

public static <T extends Comparable<T>> void QS(T array[], int start, int end) {
if (start < end) {
int PIndex = partition(array, start, end);
QS(array, start, PIndex - 1);
QS(array, PIndex + 1, end);
public static <T extends Comparable<T>> void QS(List<T> list, int left, int right) {
if (left>=right) { return }
else
{
int pivot = partition(array, left,right);
QS(list, left, pivot- 1);
QS(list, pivot + 1, right);
}
}

Expand All @@ -32,17 +34,32 @@ public static <T extends Comparable<T>> void QS(T array[], int start, int end) {
* Finds the partition index of an array
**/

public static <T extends Comparable<T>> int partition(T array[], int start, int end) {
T pivot = array[end];
int PIndex = start;
for (int i=start;i<end;i++) {
if (array[i].compareTo(pivot) <= 0) {
swap(array, i, PIndex);
PIndex++;
public static <T extends Comparable<T>> int partition(List<T> list, int left, int right) {
int mid=(left+right)/2;
T pivot=list.get(mid);
swap(list,mid,right);
while(left<right)
{
while(left<right && pivot.compareTo(list.get(left))>=0)
{
++left;
}
if(left<right)
{
swap(list,left,right);
--right;
}
while(left<right && list.get(right).compareTo(pivot)>=0)
{
--right;
}
if(left<right)
{
swap(list,left,right);
++left;
}
}
swap(array, PIndex, end);
return PIndex;
return left;
}

/**
Expand All @@ -54,39 +71,36 @@ public static <T extends Comparable<T>> int partition(T array[], int start, int
* Swaps initial and fin element
**/

public static <T extends Comparable<T>> void swap(T[] array, int initial, int fin) {
T temp = array[initial];
array[initial] = array[fin];
array[fin] = temp;
public static <T extends Comparable<T>> void swap(List<E> list, int initial, int fin) {
E temp= list.get(initial);
list.set(initial,list.get(fin));
list.set(fin,temp);
}

// Driver Program
public static void main(String[] args) {

// For integer input
int[] arr = {3,4,1,32,0,2,44,111,5};
Integer[] array = new Integer[arr.length];
for (int i=0;i<arr.length;i++) {
array[i] = arr[i];
}
ArrayList<Integer> array = new ArrayList<Integer>(9);
array = {3,4,1,32,0,2,44,111,5};

QS(array, 0, arr.length-1);
QS(array, 0, array.size()-1);

//Output => 0 1 2 3 4 5 32 44 111
for (int i=0;i<array.length;i++) {
System.out.print(array[i] + " ");
for (int i=0;i<array.size();i++) {
System.out.print(array.get(i) + " ");
}
System.out.println();

// String Input
String[] array1 = {"c", "a", "e", "b","d"};
ArrayList<String> array1=new ArrayList<String>(5);
array1 = {"c", "a", "e", "b","d"};

QS(array1, 0,array1.length-1);
QS(array1, 0,array1.size()-1);

//Output => a b c d e
for(int i=0; i<array1.length; i++)
for(int i=0; i<array1.size(); i++)
{
System.out.print(array1[i]+"\t");
System.out.print(array1.get(i)+"\t");
}
}
}
Expand Down