Question

link

Quicksort is a divide and conquer algorithm. It first divides a large list into two smaller sub-lists and then recursively sort the two sub-lists. If we want to sort an array without any extra space, Quicksort is a good option. On average, time complexity is O(n log(n)).

Solution

This question is not easy. Practise more!

Code

public static void quickSortRan(int[] arr, int low, int high) {
	if (low >= high) {
		return;
	}
	int pivot = arr[low + (high - low) / 2];
	int left = low;
	int right = high;
	while (left < right) {
		while (arr[left] < pivot) {
			left++;
		}
		while (arr[right] > pivot) {
			right--;
		}
		if (left <= right) {
			int temp = arr[left];
			arr[left] = arr[right];
			arr[right] = temp;
			left++;
			right--;
		}
	}
	quickSortRan(arr, low, right);
	quickSortRan(arr, left, high);
}