TheAlgorithms-Ruby/sorting/merge_sort.rb
2021-02-17 02:31:11 +09:00

36 lines
827 B
Ruby

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? && 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
result << if first_array.first < second_array.first
first_array.shift
else
second_array.shift
end
end
end
result
end
if $0 == __FILE__
puts 'Enter a list of numbers separated by space'
list = gets.split.map(&:to_i)
p merge_sort(list)
end