solve sum in C#

solve_sum.cs

// Solve sum in C#

static List<long> solve_sum(List<long> A, List<long> B)
    /*
    This function implements a greedy approach to minimize the sum difference
    among two sets A and B
    */
    {
        // Join A and B into a new list C
        var C =  new List<long>(); 
        C.AddRange(A); 
        C.AddRange(B);

        // Sort C in descending order for a faster search
        C = C.OrderByDescending(i => i).ToList();

        long a_sum = 0L; // initialize a_sum
        long b_sum = 0L; // initialize b_sum
        var equal_sum_set = new List<long>(); // A set containing N_1 numbers with equal sum as the N_2 numbers
        
        foreach(var item in C) // Minimize difference and distribute numbers
            {
                if (a_sum > b_sum) {
                    b_sum += item;
                    equal_sum_set.Add(item);
                } else {
                    a_sum += item;
                }
            }
        return equal_sum_set; // Return resulting set with equal_sum, sum diff is 0 now
    }