Test: I have an array of stock prices, where the index value corresponds to the time in minutes after midnight, and the value corresponds to the stock prices. Calculate the maximum profit i could make from the buy and sell of the stock.

gistfile1.rb

stock_prices = [1, 5, 8, 3, 13, 18, 11, 44]

def max_profit stock_prices
  profit_so_far = 0
  stock_prices.each_with_index do |buy_price, buy_time|
    stock_prices.each_with_index do |sell_price, sell_time|
      current_profit = buy_price - sell_price
      if current_profit > profit_so_far && buy_time < sell_time
        profit_so_far = current_profit
      end
    end
  end
  profit_so_far
end