#include <iostream>
using namespace std;

int partition(int arr[], int low, int high) 
{
    int pivot = arr[high]; //pivot element
    int i = (low - 1); //index of smaller element

    for (int j = low; j <= high - 1; j++) 
    {
        if (arr[j] <= pivot) 
        {
            i++; //increment index of smaller element
            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) 
    {
        //partition the array
        int pi = partition(arr, low, high);

        //recursively sort elements before and after partition
        quickSort(arr, low, pi - 1);
        quickSort(arr, pi + 1, high);
    }
}

void processQuickSort(int arr[], int n) 
{
    if (n > 1) 
        quickSort(arr, 0, n - 1);
}


void displayArray(int arr[], int n) {
    for (int i = 0; i < n; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
}

// Function to dynamically allocate an array and fill it with random values.
void fillDynamicArrayWithRandomValues(int** arr, int* n) {
    cout << "Enter the size of the array: ";
    cin >> *n;
    *arr = new int[*n];
    srand(time(0)); // Seed for random number generation
    for (int i = 0; i < *n; i++) {
        (*arr)[i] = rand() % 1000; // Fill with random numbers between 0 and 999
    }
}

int main() {
    int* arr;
    int n;
    fillDynamicArrayWithRandomValues(&arr, &n);
    cout << "Unsorted array: ";
    displayArray(arr, n);
    processQuickSort(arr, n);
    cout << "Sorted array: ";
    displayArray(arr, n);
    delete[] arr; // Deallocate dynamically allocated memory
    return 0;
}