In computer science, merge sort (also normally spelled mergesort) is an efficient, general-purpose, comparison-based sorting algorithm. A detailed description and analysis of bottom-up mergesort looked in a report by Goldstine and von Neumann as early as 1948.

Repeatedly merge sublists to produce new sorted sublists until there is only one sublist remaining. divide the unsorted list into N sublists, each containing one component (a list of one component is considered sorted).

```
def merge_sort(array)
return array if array.length <= 1
mid = array.length / 2
first_array = array.slice(0..mid - 1)
second_array = array.slice(mid..-1)
first_array = merge_sort first_array
second_array = merge_sort second_array
# merge
result = []
until first_array.empty? and second_array.empty?
if first_array.empty?
result.concat(second_array)
second_array.clear
elsif second_array.empty?
result.concat(first_array)
first_array.clear
else
if first_array.first < second_array.first
result << first_array.shift
else
result << second_array.shift
end
end
end
result
end
puts "Enter a list of numbers seprated by space"
list = gets
print merge_sort list.split(" ").map(&:to_i)
```