using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        int result = GetSequences(new List<int>() { 4, -1, 5, 6 }, 3, 2);

        Console.WriteLine(result);

    }

static int GetSequences(List<int> s, int d, int m)

{

    //m = segment-length

    //d = sum

​

    int count = 0;

​

    for (int start = 0, end = s.Count() - m; start < end; start++)

    {

        // there is no point using a list that you sum. You can directly sum the values in an int.

        var temp = 0;

        // temp <= d && i < m will allow you to break the loop earlier if temp become greater than d

        for (int i = 0; temp <= d && i < m; i++)

        {

            temp += s[start + i];

        }

        if (temp == d)

        {

            count++;

        }

    }

    return count;

}

}