https://www.youtube.com/watch?v=QXum8HQd_l4

								//C program to implement QuickSort
#include <stdio.h>

void swap(int* a, int* b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

int partition(int arr[], int low, int high) {
    int pivot = arr[high];
    int i = low - 1;

    for (int j = low; j <= high - 1; j++) {
        if (arr[j] < pivot) {
            i++;
            swap(&arr[i], &arr[j]);
        }
    }

    swap(&arr[i + 1], &arr[high]);
    return i + 1;
}

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);
    }
}

void printArray(int arr[], int size) {
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    printf("\\n");
}

int main() {
    int arr[] = { 5, 1, 9, 3, 7, 4, 8, 6, 2 };
    int n = sizeof(arr) / sizeof(arr[0]);
    printf("Before sorting: ");
    printArray(arr, n);

    quicksort(arr, 0, n - 1);

    printf("After sorting: ");
    printArray(arr, n);
    return 0;
}

								//Java program to implement Quicksort
public class QuickSort {
    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);
        }
    }

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

        int temp = arr[i + 1]; //swap arr[i] and piviot or arr[high]
        arr[i + 1] = arr[high];
        arr[high] = temp;
        return i + 1;
    }

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

    public static void main(String[] args) {
        int[] arr = { 5, 1, 9, 3, 7, 4, 8, 6, 2 };
        System.out.print("Before sorting: ");
        printArray(arr);

        quickSort(arr, 0, arr.length - 1);

        System.out.print("After sorting: ");
        printArray(arr);
    }
}