05quick.cpp

#include <iostream>
#include <time.h>
#define MAX 20
using namespace std;

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);
    }
}

int main()
{
    int arr[MAX], size;
    clock_t start, end;
    cout << "Enter size of array: ";
    cin >> size;
    cout << "Enter elements: ";
    for (int i=0; i<size; i++)
    {
        cin >> arr[i];
    }
    start = clock();
    quickSort(arr,0,size-1);
    end = clock();
    cout << "The sorted array is: " << endl;
    for (int i=0; i<size; i++)
    {
        cout << arr[i] << " ";
    }
    cout << endl;
    cout << "Time taken: " << double(end-start)/CLOCKS_PER_SEC << endl;
    return 0;
}