def radixSort(list) maxLen = list.max_by(&:size) maxLen.times do |j| buckets=(0..9).map{ [] } list.each do |i| buckets[i.to_s[-j - 1].to_i] << i end list = buckets.select{|i| !i.empty? }.reduce(:+) end list end nums = 20.times.map{ rand 100 } puts nums.inspect puts radixSort(nums).inspect