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Quick Sort Algorithm

 

QuickSort is a Divide and Conquer algorithm. It picks an element as a pivot and partitions the given array around the picked pivot.

Java


 public class Sort{
     public static void main(String []args){
        int[] arr = {3, 5, 1, 6, 2, 4, 8};
        quickSort(arr, 0, arr.length-1);
        for(int x:arr)
            System.out.print(x+" ");
     }
     public static int partition(int arr[], int low, int high){ 
        int pivot = arr[high];  
        int i = (low-1);
        for (int j=low; j<high; j++){ 
            if (arr[j] <= pivot){ 
                i++;  
                int temp = arr[i]; 
                arr[i] = arr[j]; 
                arr[j] = temp; 
            } 
        } 
        int temp = arr[i+1]; 
        arr[i+1] = arr[high]; 
        arr[high] = temp; 
        return i+1; 
    } 
    public static void quickSort(int arr[], int low, int high){ 
        if (low < high){ 
            int pi = partition(arr, low, high);
            quickSort(arr, low, pi-1); 
            quickSort(arr, pi+1, high); 
        } 
    } 
 }


Python


	
def quickSort(arr):
    less = []
    pivotList = []
    more = []

    if len(arr) <= 1:
        return arr
    else:
        pivot = arr[0]
        for i in arr:
            if i < pivot:
                less.append(i)
            elif i > pivot:
                more.append(i)
            else:
                pivotList.append(i)
        less = quickSort(less)
        more = quickSort(more)
        return less + pivotList + more
arr = [3, 5, 1, 6, 2, 4]
print(quickSort(arr))

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