heap_sort.cpp File Reference

Heap Sort Algorithm (heap sort) implementation More...

#include <algorithm>
#include <cassert>
#include <iostream>

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Functions
template<typename T >
void	printArray (T *arr, int sz)
template<typename T >
void	heapify (T *arr, int n, int i)
template<typename T >
void	heapSort (T *arr, int n)
void	test ()
int	main ()

Detailed Description

Heap Sort Algorithm (heap sort) implementation

Author

Ayaan Khan

Heap-sort is a comparison-based sorting algorithm. Heap-sort can be thought of as an improved selection sort: like selection sort, heap sort divides its input into a sorted and an unsorted region, and it iteratively shrinks the unsorted region by extracting the largest element from it and inserting it into the sorted region. Unlike selection sort, heap sort does not waste time with a linear-time scan of the unsorted region; rather, heap sort maintains the unsorted region in a heap data structure to more quickly find the largest element in each step.

Time Complexity - \(O(n \log(n))\)

Function Documentation

main()

int main

(

void

)

Main function

           {
    test();
    return 0;
}

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printArray()

template<typename T >

void printArray	(	T *	arr,
		int	sz )

Utility function to print the array after sorting.

Parameters

arr	array to be printed
sz	size of array

                                {
    for (int i = 0; i < sz; i++) std::cout << arr[i] << "  ";
    std::cout << "\n";
}

test()

void test

(

)

Test cases to test the program

            {
    std::cout << "Test 1\n";
    int arr[] = {-10, 78, -1, -6, 7, 4, 94, 5, 99, 0};
    int sz = sizeof(arr) / sizeof(arr[0]);  // sz - size of array
    printArray(arr, sz);  // displaying the array before sorting
    heapSort(arr, sz);    // calling heapsort to sort the array
    printArray(arr, sz);  // display array after sorting
    assert(std::is_sorted(arr, arr + sz));
    std::cout << "Test 1 Passed\n========================\n";
 
    std::cout << "Test 2\n";
    double arr2[] = {4.5, -3.6, 7.6, 0, 12.9};
    sz = sizeof(arr2) / sizeof(arr2[0]);
    printArray(arr2, sz);
    heapSort(arr2, sz);
    printArray(arr2, sz);
    assert(std::is_sorted(arr2, arr2 + sz));
    std::cout << "Test 2 passed\n";
}

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