using System;

public class Program

{

    public static void Main()

    {

        //Console.WriteLine("Hello World");

        int[] arr = {10,2,3,6,8,11,15};

        var maxDiff = MaxDiff_Solution2(arr);

        Console.WriteLine(maxDiff);

    }

    public static int MaxDiff_Solution2(int []numbers) {

        int length = numbers.Length;

        if(numbers == null && length < 2)

            return 0;

        int min = numbers[0];

        int maxDiff = numbers[1] - min;

        for(int i = 2; i < length; ++i) {

        if(numbers[i - 1] < min)

        min = numbers[i - 1];

        int currentDiff = numbers[i] - min;

        if(currentDiff > maxDiff)

        maxDiff = currentDiff;

        }

        return maxDiff;

        }

}