用Ruby实现从输入数组中剔除元素的merge_sort算法

def merge_sort(arr)
  return arr if arr.length <= 1

  mid = arr.length / 2
  left = merge_sort(arr[0...mid])
  right = merge_sort(arr[mid..-1])

  merge(left, right)
end

def merge(left, right)
  result = []
  i = j = 0

  while i < left.length && j < right.length
    if left[i] < right[j]
      result << left[i]
      i += 1
    else
      result << right[j]
      j += 1
    end
  end

  result.concat(left[i..-1]) if i < left.length
  result.concat(right[j..-1]) if j < right.length

  result
end

# 示例用法
input = [5, 2, 8, 3, 1, 9, 4, 7, 6]
output = merge_sort(input)
puts output.inspect