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quickSort.cpp
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quickSort.cpp
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/* C++ implementation of QuickSort */
#include <bits/stdc++.h>
using namespace std;
/**
* Custom Swap function
* @param a
* @param b
**/
void swap(int* a, int* b)
{
int t = *a;
*a = *b;
*b = t;
}
/**
* This function takes last element as pivot, places
* the pivot element at its correct position in sorted
* array, and places all smaller to left of pivot and all greater elements to right
* of pivot
* @param arr
* @param low
* @param high
* @return int
**/
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);
}
/**
* The main function that implements QuickSort
* @param arr
* @param low
* @param high
**/
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);
}
}
/**
* Function to print array
* @param arr
* @param size
**/
void printArray(int arr[], int size)
{
int i;
for (i = 0; i < size; i++)
cout << arr[i] << " ";
cout << endl;
}
int main()
{
cout << "Please enter the number of items you want to sort" << endl;
int n,i;
cin >> n;
int arr[n];
for(i=0; i<n ;i++)
{
cin >> arr[i];
}
quickSort(arr, 0, n - 1);
cout << "Sorted array: \n";
printArray(arr, n);
return 0;
}