optimal merge PATTERN using greedy method

 The algorithm can be described as follows:

1. Sort the list of files in ascending order of their sizes.
2. Initialize a heap data structure with the sizes of the files.
3. While the heap contains more than one element: a. Extract the two smallest elements from the heap. b. Merge the two files into a single file, and add the size of the merged file to the total work done. c. Add the size of the merged file to the heap.
4. Return the total work done.

This approach works because it always merges the two smallest files at each step, which minimizes the amount of work required to merge all the files. The time complexity of this algorithm is O(nlogn) due to the use of the heap data structure, where n is the number of files.