def max_profit(prices):
  # Initialize two pointers and maximum profit variable
  buy = 0
  sell = 1 
  maxprofit = 0

  # Iterating over the prices array
  while sell < len(prices):
      # Calculating the current profit
      currentprofit = prices[sell] - prices[buy]
      # Setting the maximum profit if price at sell pointer is greater than buy
      if prices[buy] < prices[sell]:
          maxprofit = max(currentprofit, maxprofit)
      # Otherwise, update buy to be equal to sell
      else:
          buy = sell
      
      # Moving sell pointer to the next index of the prices array
      sell += 1
      
  return maxprofit

# Driver code
def main():
    prices = [
                [1, 2, 4, 2, 5, 7, 2, 4, 9, 0, 9],
                [8, 2, 6, 4, 7, 5],
                [7, 6, 4, 3, 1],
                [2, 6, 8, 7, 8, 7, 9, 4, 1, 2, 4, 5, 8],
                [1, 2]
             ]

    for i in range(len(prices)):
        print(i + 1, ". Stock prices = ", prices[i], sep="")
        print("   Maximum profit = ", max_profit(prices[i]), sep="")
        print("-" * 100)


if __name__ == "__main__":
    main()