When is Mergesort a good choice for sorting an array?

We need a reasonably fast algorithm with a good worst case cost
  • Each record requires a large amount of memory
  • Each record requires a small amount of memory
  • The processor speed is fast
  • The array contains many records
  • We need good best-case running time
  • None of these situations

Does Mergesort's number of comparisons depend on the particular order of the input array?

No, it does not.

This makes it reliable in the worst case