Last Updated: 2 Apr, 2021
Convert Min Heap To Max Heap
Moderate
Asked in companies
You are given an array of size ‘N’ which is an array representation of min-heap.
You need to convert this min-heap array representation to a max-heap array representation. Return the max-heap array representation.
For Example
Corresponding to given min heap : [1,2,3,6,7,8]
It can be converted to the following max heap: [8,7,3,6,2,1]
Input Format:
The first line contains a single integer ‘N’ denoting the size of the array.
The next line contains ‘N’ space-separated integers denoting the array representation of min-heap.
Output Format
There can be many possible max-heaps. Return any possible max-heap for given input min-heap.
Approaches
The main idea is that when an array is sorted in descending order it becomes max heap as for every ‘i’ from i=0 to n/2 it is greater than equal to arr[2*i+1] and arr[2*i+2].
The main idea is to build max-heap for the given input array just like in heapsort. It will convert the input array into a max heap. We will perform the heapify(Refer Heap Sort Algorithm) process to the given input array to build the heap. In a max heap, if arr[ i ] is less than it’s it children node arr[2*i+1] and arr[2*i+2] then replace it with children and call heapfiy on the corresponding child node.Heapify can only be applied to a node only when its children are heapified. Hence it must be performed in bottom-up order.