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formatting source-code for e464ddac36

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github-actions 2020-06-20 18:34:51 +00:00 committed by Ayaan Khan
parent 38db7fdec0
commit 11728ee231
1 changed files with 26 additions and 26 deletions
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52
sorting/heap_sort.cpp
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@ -8,24 +8,24 @@
* \author [Ayaan Khan](http://github.com/ayaankhan98) * \author [Ayaan Khan](http://github.com/ayaankhan98)
* *
* \details * \details
* heapsort is a comparison-based sorting algorithm. * heapsort is a comparison-based sorting algorithm.
* Heapsort can be thought of as an improved selection sort: * Heapsort can be thought of as an improved selection sort:
* like selection sort, heapsort divides its input into a sorted * like selection sort, heapsort divides its input into a sorted
* and an unsorted region, and it iteratively shrinks the unsorted * and an unsorted region, and it iteratively shrinks the unsorted
* region by extracting the largest element from it and inserting * region by extracting the largest element from it and inserting
* it into the sorted region. Unlike selection sort, * it into the sorted region. Unlike selection sort,
* heapsort does not waste time with a linear-time scan of the * heapsort does not waste time with a linear-time scan of the
* unsorted region; rather, heap sort maintains the unsorted region * unsorted region; rather, heap sort maintains the unsorted region
* in a heap data structure to more quickly find the largest element * in a heap data structure to more quickly find the largest element
* in each step. * in each step.
* *
* Time Complexity - O(nlog(n)) * Time Complexity - O(nlog(n))
* *
*/ */
#include <iostream> #include <iostream>
/** /**
* *
* Utility Lambda function to print the array after * Utility Lambda function to print the array after
* sorting. * sorting.
* *
@ -33,23 +33,24 @@
* @param sz size of array * @param sz size of array
* *
*/ */
auto printArray = [] (int *arr, int sz) { auto printArray = [](int *arr, int sz) {
for (int i = 0 ; i < sz ; i++) for (int i = 0; i < sz; i++) std::cout << arr[i] << " ";
std::cout << arr[i] <<" ";
std::cout << "\n"; std::cout << "\n";
}; };
/** /**
* *
* The heapify procedure can be thought of as building a heap from * The heapify procedure can be thought of as building a heap from
* the bottom up by successively sifting downward to establish the * the bottom up by successively sifting downward to establish the
* heap property. * heap property.
* *
* @param arr array be to sorted
* @param
*/ */
void(*heapify)(int *arr, int n, int i) = [] (int *arr, int n, int i) { void (*heapify)(int *arr, int n, int i) = [](int *arr, int n, int i) {
int largest = i; int largest = i;
int l = 2*i + 1; int l = 2 * i + 1;
int r = 2*i + 2; int r = 2 * i + 2;
if (l < n && arr[l] > arr[largest]) if (l < n && arr[l] > arr[largest])
largest = l; largest = l;
@ -71,11 +72,10 @@ void(*heapify)(int *arr, int n, int i) = [] (int *arr, int n, int i) {
* @param n size of array * @param n size of array
* *
*/ */
auto heapSort = [] (int *arr, int n) { auto heapSort = [](int *arr, int n) {
for (int i = n-1 ; i >= 0; i--) for (int i = n - 1; i >= 0; i--) heapify(arr, n, i);
heapify(arr, n, i);
for (int i = n-1 ; i >= 0; i--) { for (int i = n - 1; i >= 0; i--) {
std::swap(arr[0], arr[i]); std::swap(arr[0], arr[i]);
heapify(arr, i, 0); heapify(arr, i, 0);
} }
@ -86,7 +86,7 @@ int main() {
int arr[] = {-10, 78, -1, -6, 7, 4, 94, 5, 99, 0}; int arr[] = {-10, 78, -1, -6, 7, 4, 94, 5, 99, 0};
int sz = sizeof(arr) / sizeof(arr[0]); // sz - size of array int sz = sizeof(arr) / sizeof(arr[0]); // sz - size of array
printArray(arr, sz); // displaying the array before sorting printArray(arr, sz); // displaying the array before sorting
heapSort(arr, sz); // calling heapsort to sort the array heapSort(arr, sz); // calling heapsort to sort the array
printArray(arr, sz); // display array after sorting printArray(arr, sz); // display array after sorting
return 0; return 0;
} }