A well-known variant of counting sort is tally sort, where the input is known to contain
no duplicate elements, or where we wish to eliminate duplicates during sorting. In this
case the count array can be represented as a bit array; a bit is set if that key value was observed in the input array. Tally sort is widely familiar because of its use in the book
Programming Pearls as an example of an unconventional solution to a particular set of
limitation