Lecture 326:- Creating a Heap

Creating a heap involves initializing an empty heap and inserting elements into it to satisfy the heap property. Here's a C++ program to create a max heap and insert elements into it:

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#include <iostream> #include <vector> using namespace std; // Function to heapify (bubble-up) the newly inserted element in a max heap void maxHeapify(vector<int>& heap, int index) {    int parent = (index - 1) / 2;    if (parent >= 0 && heap[index] > heap[parent]) {        swap(heap[index], heap[parent]);        maxHeapify(heap, parent);    } } // Function to insert an element into a max heap void insertMaxHeap(vector<int>& heap, int element) {    heap.push_back(element); // Add the element at the last position    maxHeapify(heap, heap.size() - 1); // Heapify the new element } // Function to display the elements of the heap void displayHeap(const vector<int>& heap) {    for (int element : heap) {        cout << element << " ";    }    cout << endl; } int main() {    vector<int> maxHeap;    // Insert elements into the max heap    insertMaxHeap(maxHeap, 10);    insertMaxHeap(maxHeap, 20);    insertMaxHeap(maxHeap, 15);    insertMaxHeap(maxHeap, 30);    insertMaxHeap(maxHeap, 40);    // Display the max heap    cout << "Max Heap: ";    displayHeap(maxHeap);    return 0; }

In this program, we first define the maxHeapify function, which performs the "bubble-up" operation to maintain the heap property after inserting an element into the max heap. The insertMaxHeap function inserts an element into the max heap by adding it to the last position and then calling maxHeapify to rearrange the elements and satisfy the heap property. The displayHeap function is provided to print the elements of the max heap.

When you run this C++ program, it will create a max heap and display its elements in descending order (since it's a max heap). You can modify the elements and their order to create different max heaps or even create a min heap by modifying the maxHeapify function to create a min heap.