Stock Picker solution from The Odin Project

stock-picker.rb

def stock_picker prices
  best_days = []
  profit = 0
  i = 0

  while i < prices.length - 1
    j = i

    while j < prices.length
      possible_profit = prices[j] - prices[i]

      if possible_profit > profit
        profit = possible_profit
        best_days = [i, j]
      end

      j += 1
    end

    i += 1
  end

  best_days
end

p stock_picker([17,3,6,9,15,8,6,1,10]) == [1, 4]
p stock_picker([1, 15]) == [0, 1]
p stock_picker([15, 1]) == []
p stock_picker([15, 1, 2, 3]) == [1, 3]
p stock_picker([15, 2, 2, 3]) == [1, 3]
p stock_picker([15, 3, 2, 3]) == [2, 3]