JAVA quick_sort.java

class QuickSort
{
	
	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++;

				// swap arr[i] and arr[j]
				int temp = arr[i];
				arr[i] = arr[j];
				arr[j] = temp;
			}
		}

		// swap arr[i+1] and arr[high] (or pivot)
		int temp = arr[i+1];
		arr[i+1] = arr[high];
		arr[high] = temp;

		return i+1;
	}


	void sort(int arr[], int low, int high)
	{
		if (low < high)
		{
			
			int pi = partition(arr, low, high);

			sort(arr, low, pi-1);
			sort(arr, pi+1, high);
		}
	}

	static void printArray(int arr[])
	{
		int n = arr.length;
		for (int i=0; i<n; ++i)
			System.out.print(arr[i]+" ");
		System.out.println();
	}

	
	public static void main(String args[])
	{
		int arr[] = {10, 7, 8, 9, 1, 5};
		int n = arr.length;

		QuickSort ob = new QuickSort();
		ob.sort(arr, 0, n-1);

		System.out.println("sorted array");
		printArray(arr);
	}
}