using System;

​

public class Program

{

    public static void Main(string[] args)

    {

        int[] nums = { -2, 1, -3, 4, -1, 2, 1, -5, 4 };

        int maxSubarraySum = FindMaximumSubarraySum(nums);

        Console.WriteLine("Maximum subarray sum: " + maxSubarraySum);

    }

    public static int FindMaximumSubarraySum(int[] nums)

    {

        if (nums == null || nums.Length == 0)

        {

            throw new ArgumentException("Input array cannot be null or empty.");

        }

​

        int maxSum = nums[0];

        int currentSum = nums[0];

​

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

        {

            // Choose whether to extend the subarray or start a new subarray

            currentSum = Math.Max(nums[i], currentSum + nums[i]);

​

            // Update the maximum sum if the current sum is greater

            maxSum = Math.Max(maxSum, currentSum);

        }

​

        return maxSum;

    }

}

​