It's used in one of the fastest sorting approaches - counting sort / binning - to compute the location of where to store the sorted/binned items. First you coun

It's used in one of the fastest sorting approaches - counting sort / binning - to compute the location of where to store the sorted/binned items. First you count the number of items per bin, then you use prefix-sums to compute the memory location of each bin, then you insert the items into the respective bins. Some radix-sort implementations also utilize counting sort under the hood, and therefore prefix-sums. (Not sure if all radix-sort implementations need it)