dwa_1064_qsort.java

public class QSort{
    
    static void printArray(int[] arr, int size)
        {
            for(int i = 0; i < size; i++)
                System.out.print(arr[i] + " ");
                 
            System.out.println();
        }
    
    static int  partition(int[] arr, int low, int high)
    {
     
    int pivot = arr[high];
    int partition_index = low;
    int temp ;
  
        for(int itr = low; itr <= high - 1; itr++)
        {
            if (arr[itr] < pivot)
            {
                temp = arr[itr];
                arr[itr] = arr[partition_index];
                arr[partition_index] = temp;
                partition_index += 1;
            }
        }
        temp = arr[high];
        arr[high] = arr[partition_index];
        arr[partition_index] = temp;
        
        return partition_index;

   }
    
    static void qsort(int[] arr, int low, int high){
        if (low < high){
            int partition_index = partition(arr, low, high);
            qsort(arr, low, partition_index-1);
            qsort(arr, partition_index+1, high);
        }
    }
    
     public static void main(String []args){
        int arr[] = {3, 8, 6, 2, 4, 7, 8, 5};
        qsort(arr, 0, arr.length-1);
        printArray(arr, 8);
        
     }
}