From e5cc7ee6d108f440331206cfe8dcf38c924751db Mon Sep 17 00:00:00 2001 From: Lovecase Singh <76085767+Lovecase@users.noreply.github.com> Date: Fri, 6 Oct 2023 21:59:37 +0530 Subject: [PATCH] Create QuickSort.cpp Wrote a implementation of quicksort algorithm --- QuickSort.cpp | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 QuickSort.cpp diff --git a/QuickSort.cpp b/QuickSort.cpp new file mode 100644 index 00000000..fb9decfa --- /dev/null +++ b/QuickSort.cpp @@ -0,0 +1,79 @@ + +#include +using namespace std; + +// function to swap elements +void swap(int *a, int *b) { + int t = *a; + *a = *b; + *b = t; +} + +// function to print the array +void printArray(int array[], int size) { + int i; + for (i = 0; i < size; i++) + cout << array[i] << " "; + cout << endl; +} + +// function to rearrange array (find the partition point) +int partition(int array[], int low, int high) { + + // select the rightmost element as pivot + int pivot = array[high]; + + // pointer for greater element + int i = (low - 1); + + // traverse each element of the array + // compare them with the pivot + for (int j = low; j < high; j++) { + if (array[j] <= pivot) { + + // if element smaller than pivot is found + // swap it with the greater element pointed by i + i++; + + // swap element at i with element at j + swap(&array[i], &array[j]); + } + } + + // swap pivot with the greater element at i + swap(&array[i + 1], &array[high]); + + // return the partition point + return (i + 1); +} + +void quickSort(int array[], int low, int high) { + if (low < high) { + + // find the pivot element such that + // elements smaller than pivot are on left of pivot + // elements greater than pivot are on righ of pivot + int pi = partition(array, low, high); + + // recursive call on the left of pivot + quickSort(array, low, pi - 1); + + // recursive call on the right of pivot + quickSort(array, pi + 1, high); + } +} + +// Driver code +int main() { + int data[] = {8, 7, 6, 1, 0, 9, 2}; + int n = sizeof(data) / sizeof(data[0]); + + cout << "Unsorted Array: \n"; + printArray(data, n); + + // perform quicksort on data + quickSort(data, 0, n - 1); + + cout << "Sorted array in ascending order: \n"; + printArray(data, n); +}