Write in c++ MinHeap program? In this assignment you will be working with minhea

Question

Write in c++ MinHeap program?

In this assignment you will be working with minheaps, and operations Insert, Delete, and Change. Your input file consists of data items, together with some information which tells you what to do with them. Each data item is a real number. The size of the array can be taken to be 500. The first character in each line of your input file tells you what operation to perform on the data item listed in that line. "I" stands for insert, D stands for delete, and C stands for change. P stands for printing the data during a POSTORDER traversal of the tree. For example, consider the following input file:

I 1

I 5

I 7

P

C 7 10

P

I 10

I 3

P

C 10 20

P

Then, the output will be:

5, 7, 1

5, 10, 1

10, 5, 3, 10, 1

20, 5, 3, 20, 1

Please use standdard input and output function and "cin". Note that to perform Change and Delete, you have to find the item first, and this requires a search. So C 10 20 means that your program searches for 10. If it finds it, it changes all occurrences of 10 to 20 and also adjusts the heap. Note further that we allow duplicates, so Change and Delete operations must change all occurrences of the data stored in the heap. Your Program must read from an input file and must write to an output file. Use the project command to submit this assigned to project PROGRAM4. You must submit the files containing your C++ code. If your program has any special compilation instructions (beyond g++ progname.cpp), you must also include a read-me file listing the proper commands.

Explanation / Answer

// A C++ program to implement miniHeap Operations
#include<iostream>
#include<climits>
using namespace std;

// Prototype of a utility function to swap two integers
void swap(int *x, int *y);

// A class for Min Heap
class MinHeap
{
    int *harr; // pointer to array of elements in heap
    int capacity; // maximum possible size of min heap
    int heap_size; // Current number of elements in min heap
public:
    // Constructor
    MinHeap(int capacity);

    // to heapify a subtree with root at given index
    void MinHeapify(int );

    int parent(int i) { return (i-1)/2; }

    // to get index of left child of node at index i
    int left(int i) { return (2*i + 1); }

    // to get index of right child of node at index i
    int right(int i) { return (2*i + 2); }

    // to extract the root which is the minimum element
    int extractMin();

    // Decreases key value of key at index i to new_val
    void decreaseKey(int i, int new_val);

    // Returns the minimum key (key at root) from min heap
    int getMin() { return harr[0]; }

    // Deletes a key stored at index i
    void deleteKey(int i);

    // Inserts a new key 'k'
    void insertKey(int k);
};

// Constructor: Builds a heap from a given array a[] of given size
MinHeap::MinHeap(int cap)
{
    heap_size = 0;
    capacity = cap;
    harr = new int[cap];
}

// Inserts a new key 'k'
void MinHeap::insertKey(int k)
{
    if (heap_size == capacity)
    {
        cout << " Overflow: Could not insertKey ";
        return;
    }

    // First insert the new key at the end
    heap_size++;
    int i = heap_size - 1;
    harr[i] = k;

    // Fix the min heap property if it is violated
    while (i != 0 && harr[parent(i)] > harr[i])
    {
       swap(&harr[i], &harr[parent(i)]);
       i = parent(i);
    }
}

// Decreases value of key at index 'i' to new_val. It is assumed that
// new_val is smaller than harr[i].
void MinHeap::decreaseKey(int i, int new_val)
{
    harr[i] = new_val;
    while (i != 0 && harr[parent(i)] > harr[i])
    {
       swap(&harr[i], &harr[parent(i)]);
       i = parent(i);
    }
}

// Method to remove minimum element (or root) from min heap
int MinHeap::extractMin()
{
    if (heap_size <= 0)
        return INT_MAX;
    if (heap_size == 1)
    {
        heap_size--;
        return harr[0];
    }

    // Store the minimum vakue, and remove it from heap
    int root = harr[0];
    harr[0] = harr[heap_size-1];
    heap_size--;
    MinHeapify(0);

    return root;
}


// This function deletes key at index i. It first reduced value to minus
// infinite, then calls extractMin()
void MinHeap::deleteKey(int i)
{
    decreaseKey(i, INT_MIN);
    extractMin();
}

// A recursive method to heapify a subtree with root at given index
// This method assumes that the subtrees are already heapified
void MinHeap::MinHeapify(int i)
{
    int l = left(i);
    int r = right(i);
    int smallest = i;
    if (l < heap_size && harr[l] < harr[i])
        smallest = l;
    if (r < heap_size && harr[r] < harr[smallest])
        smallest = r;
    if (smallest != i)
    {
        swap(&harr[i], &harr[smallest]);
        MinHeapify(smallest);
    }
}

// A utility function to swap two elements
void swap(int *x, int *y)
{
    int temp = *x;
    *x = *y;
    *y = temp;
}

// Driver program to test above functions
int main()
{
    MinHeap h(11);
    h.insertKey(3);
    h.insertKey(2);
    h.deleteKey(1);
    h.insertKey(15);
    h.insertKey(5);
    h.insertKey(4);
    h.insertKey(45);
    cout << h.extractMin() << " ";
    cout << h.getMin() << " ";
    h.decreaseKey(2, 1);
    cout << h.getMin();
    return 0;
}

OUTPUT: 2 4 1

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