80% -> 85%
80% -> 85%

I looked at stable_sort's implementation and saw that it uses pointer math for its merge rather than integer math, so I tried it and got a 5% boost in speed. I also changed the merge_index for loops to while (decimal < size), which was slightly faster.
BonzaiThePenguin/WikiSort,BonzaiThePenguin/WikiSort,BonzaiThePenguin/WikiSort