using System;

public class Program

{

        public static void Main(string[] args)

        {

            int[] prices = { 20, 150, 10, 200, 5, 25, 400 };

​

            Console.WriteLine(MaxProfit(prices));

        }

​

        public static int MaxProfit(int[] sharePrices)

        {

            if (sharePrices.Length < 1) 

                return 0;

​

            int lowBuy = sharePrices[0];

            int maxProfit = 0;

​

            for (int i = 1; i < sharePrices.Length; i++)

            {

                if (sharePrices[i] < lowBuy)

                    lowBuy = sharePrices[i];

                else if (sharePrices[i] - lowBuy > maxProfit)

                    maxProfit = sharePrices[i] - lowBuy;

            }

            return maxProfit;

        }

}