ruby 归并排序

[ruby]代码库

def merge(l, r)
  result = []
  while l.size > 0 and r.size > 0 do
    if l.first < r.first
      result << l.shift
    else
      result << r.shift
    end
  end
  if l.size > 0
    result += l
  end
  if r.size > 0
    result += r
  end
  return result
end

def merge_sort(a)
  return a if a.size <= 1
  middle = a.size / 2
  left = merge_sort(a[0, middle])
  right = merge_sort(a[middle, a.size - middle])
  merge(left, right)
end