Merge pull request #741 from nlok5923/heapsort

Added heap_sort [C++]

Author: theyashshahs

heap_sort/heapsort.cpp

@@ -0,0 +1,58 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void swap(int array[], int index1, int index2) //swapping function wihout using third variable
+{
+	array[index1] = array[index1] + array[index2];
+	array[index2] = array[index1] - array[index2];
+	array[index1] = array[index1] - array[index2];
+}
+void heapify(int array[], int size, int index)
+{
+	int largest = index; //considering largest as root
+	int left = 2 * index + 1;
+	int right = 2 * index + 2;
+
+	if (left < size && array[left] > array[largest]) //left child is larger then root
+		largest = left;
+
+	if (right < size && array[right] > array[largest]) //right child is larger then root
+		largest = right;
+
+	if (largest != index) //condition if largest is not root
+	{
+		swap(array, index, largest);
+		heapify(array, size, largest);
+	}
+}
+void heapsort(int array[], int size)
+{
+
+	for (int i = size / 2 - 1; i >= 0; i--) //Create heap from array rearrangement
+		heapify(array, size, i);
+
+	for (int i = size - 1; i > 0; i--) //move current root to end a step for Extract min process
+	{
+
+		swap(array, 0, i); //swap element
+
+		heapify(array, i, 0); //excecuting heapify to bring all elements in correct position again
+	}
+}
+void display(int array[], int size)
+{
+	int i = 0;
+	for (i = 0; i < size; i++)
+		cout << array[i] << " ";
+	cout << endl;
+}
+int main()
+{
+	int array[] = {6, 3, 6, 343, 42, 1, 43, 35, 34, 43};
+	int size = sizeof(array) / sizeof(array[0]);
+	cout << "Unsorted array is :" << endl;
+	display(array, size); //display the unsorted array
+	heapsort(array, size);
+	cout << "sorted array is :" << endl;
+	display(array, size); //display the sorted array
+}