sort assignment using merge sort

merge_sort.rb

def merge_sort(arr)
  def merge(left_side, right_side)
    result = []
    left = 0
    right = 0

    loop do 
      break if right >= right_side.length && left >= left_side.length
        
      if right >= right_side.length || (left < left_side.length && left_side[left] < right_side[right]) 
        result << left_side[left]
        left += 1
      else
        result << right_side[right]
        right += 1
      end
    end

    return result
  end

  def merge_arr(arr_half)
    return arr_half if arr_half.length <= 1

    mid = arr_half.length/2 - 1
    left_side = merge_arr(arr_half[0..mid])
    right_side = merge_arr(arr_half[mid+1..-1])
    return merge(left_side, right_side)
  end

  merge_arr(arr)
end


# Find the maximum 
def maximum(arr)
  merge_sort(arr).last
end

def minimum(arr)
  merge_sort(arr).first
end

# expect it to return 42 below
result = maximum([2, 42, 22, 02])
puts "max of 2, 42, 22, 02 is: #{result}"

# expect it to return 2 below
result = minimum([2, 42, 22, 02])
puts "min of 2, 42, 22, 02 is: #{result}"

 
# expect it to return nil when empty array is passed in
result = maximum([])
puts "max on empty set is: #{result.inspect}"
result = minimum([])
puts "min on empty set is: #{result.inspect}"
 
result = maximum([-23, 0, -3])
puts "max of -23, 0, -3 is: #{result}"
 
result = maximum([6])
puts "max of just 6 is: #{result}"

require 'benchmark'
puts Benchmark.measure {merge_sort [2, 42, 22, 02]}   
puts Benchmark.measure {[2, 42, 22, 02].sort}