radix sort Algorithm
radix sort can be apply to data that can be sorted lexicographically, be they integers, words, punch cards, playing cards, or the mail. It avoids comparison by make and distribute components into buckets according to their radix. radix sorting algorithms get into common purpose as a manner to sort punched cards as early as 1923.The first memory-efficient computer algorithm was developed in 1954 at MIT by Harold H. Seward. The linear scan is closely associated to Seward's other algorithm — counting sort. computerize radix kinds had previously been dismissed as impractical because of the perceived need for variable allocation of buckets of unknown size.
# This is a pure ruby implementation of the radix sort algorithm
# the function returns collection ordered by ascending
# Example:
# pry(main)> radix_sort([6, 22, 43, 16, 0, 15, 9])
# => [0, 6, 9, 15, 16, 22, 43]
def radix_sort(array, base = 10)
# passes count equals to the number of digits in the longest number
passes = (Math.log(array.minmax.map(&:abs).max) / Math.log(base)).floor + 1
passes.times do |i|
buckets = Array.new(2 * base) { [] }
base_i = base**i
# elements are added to buckets
# according to the current place-value digit
array.each do |j|
n = (j / base_i) % base
n += base if j >= 0
buckets[n] << j
end
array = buckets.flatten
end
array
end
