Minimum operations to make Array elements 0 by decrementing pair or single element

Given an array arr[] of dimension N, the duty is to search out the minimal variety of operations required to scale back all three parts of the array to zero. Following operations are allowed:

• Scale back 2 totally different array parts by one.
• Scale back a single array ingredient by one.

Instance:

Enter: arr[] = {1, 2, 3}, N = 3
Output: 3
Rationalization : Operation 1: scale back 3 and a couple of to get {1, 1, 2}
Operation 2: reduuce 1 and a couple of to get {1, 0, 1}
Operation 3: scale back each 1s to get {0, 0, 0}

Enter: arr[] = {5, 1, 2, 9, 8}, N = 5
Output: 13

Method:

This drawback might be solved utilizing grasping method. The thought is to scale back the two largest parts at a time or (if not doable) 1 at a time.  As we want the most important parts in every step, we are able to use a max heap.

The next steps might be taken to unravel this method:

• Provoke a rely variable as 0.
• Insert all the weather in a max heap.
  • Scale back the 2 largest parts.
  • Insert the diminished values once more into the heap.
• Repeat above talked about steps till all array parts turn out to be zero and improve the rely at every iteration.
• Cease when all array parts are zero.

Beneath is the implementation of the above method:

Time Complexity: O(N * logN)
Auxiliary Area: O(N)