How does the quicksort algorithm work in Java?

How does the quicksort algorithm work in Java?

Quicksort is a divide-and-conquer algorithm that sorts an array by selecting a 'pivot' element and partitioning the other elements into two sub-arrays.

Can you show me a simple implementation of quicksort in Java?

Sure! Here's a basic implementation:

public class QuickSort {
    public static void quickSort(int[] array, int low, int high) {
        if (low < high) {
            int pivotIndex = partition(array, low, high);
            quickSort(array, low, pivotIndex - 1);
            quickSort(array, pivotIndex + 1, high);
        }
    }

    private static int partition(int[] array, int low, int high) {
        int pivot = array[high];
        int i = (low - 1);
        for (int j = low; j < high; j++) {
            if (array[j] < pivot) {
                i++;
                int temp = array[i];
                array[i] = array[j];
                array[j] = temp;
            }
        }
        int temp = array[i + 1];
        array[i + 1] = array[high];
        array[high] = temp;
        return i + 1;
    }
}

What is the time complexity of quicksort?

The average time complexity of quicksort is O(n log n), but in the worst case, it can degrade to O(n²) if the pivot is poorly chosen.