Ruby Exercise: https://www.interviewcake.com/question/stock-price

getMaxProfit.rb

def getMaxProfit(stock_prices_yesterday)
  if stock_prices_yesterday.index(stock_prices_yesterday.min) < stock_prices_yesterday.index(stock_prices_yesterday.max)
    max_profit = (stock_prices_yesterday.max - stock_prices_yesterday.min)
  else
    possible_profits = []
    
    minIndex = 0
    maxIndex = stock_prices_yesterday.length
    
    stock_prices_yesterday[0...(maxIndex-1)].each do |i|
      stock_prices_yesterday[minIndex...maxIndex].each do |j|
          possible_profits.push(j - i)
      end
      minIndex += 1
    end
    max_profit = possible_profits.max
  end
  
  puts "max profit: " + max_profit.to_s
end

getMaxProfit([11, 10, 9, 8, 7])

For some reason it's not showing negative results for when the prices go down all day..