What are the applications of merge sort in real life world?
EDIT
Let me give an example of MergeSort from my real life. I have two sets of graded papers from the same class and both sets are alphabetized. If I want to merge the two piles into one, I don't have to start all over again, I can use the work that's already been down alphabetizing them separately. The first paper on the merged list has to be either the top paper from list #1 or the top from list #2. I take that paper and put it on a new stack face down. Now I make the comparison between the new two papers on top of the stacks and put it face down on the new stack, again and again, until all the papers are on the new stack face down. Once one of the original stacks is depleted, there are no more comparisons to be made and I can put the rest of the remaining stack face down on top of the merged stack, turn it back face up and it is completely sorted.