C# Part II Arrays Exercise 8

//Write a program that finds the sequence of maximal sum in given array. Example:{2, 3, -6, -1, 2, -1, 6, 4, -8, 8} -> {2, -1, 6, 4}
//Can you do it with only one loop (with single scan through the elements of the array)?

using System;

class SequenceOfMaxSum
{
    static void Main()
    {
        int arrayLength;

        Console.Write("Enter the array's length: ");

        while (!int.TryParse(Console.ReadLine(), out arrayLength) || arrayLength <= 0)
        {
            Console.Write("Invalid input. Enter a positive integer number: ");
        }

        int[] array = new int[arrayLength];

        for (int i = 0; i < arrayLength; i++)
        {
            Console.Write("Enter the {0} element of the  array: ", i);

            while (!int.TryParse(Console.ReadLine(), out array[i]))
            {
                Console.Write("Invalid input. Enter an integer number: ");
            }
        }

        int maxSum = array[0];
        int currentSum = array[0];
        int startIndex = 0;
        int endIndex = 0;
        int bestStart = startIndex;
        int bestEnd = endIndex;

        for (int i = 1; i < array.Length; i++)
        {
            if (currentSum > 0)
            {
                if (currentSum > maxSum)
                {
                    maxSum = currentSum;
                    bestStart = startIndex;
                    endIndex = i;
                    bestEnd = endIndex;
                }
                currentSum += array[i];
            }
            else
            {
                currentSum = array[i];
                startIndex = i;
                endIndex = i;
            }
        }

        if (currentSum > maxSum)
        {
            maxSum = currentSum;
            bestStart = startIndex;
            bestEnd = array.Length;
        }

        int[] maxSequence = new int[bestEnd - bestStart];

        for (int i = bestStart, j = 0; i < bestEnd; i++, j++)
        {
            maxSequence[j] = array[i];
        }

        Console.WriteLine("The sequence {0} has maximal sum {1}.", string.Join(", ", maxSequence), maxSum);
    }
}