using System;

​

public class Program

{

    public static void Main()

    {

        var homePhone = "home";

        var cellPhone = "cell";

        var workPhone = "work";

        var phoneType = "WorkPhone";

        var phoneTypePref = "HomePhone";

        int result = getPhoneIndex(phoneTypePref, homePhone, cellPhone, workPhone, phoneType);

        Console.WriteLine(result);

    }

​

    static int getPhoneIndex(string phoneTypePref, string homePhone, string cellPhone, string workPhone, string phoneType)

    {

        string[] phoneNums = {homePhone,cellPhone,workPhone};

        string[] phoneTypes = {"HomePhone","CellPhone","WorkPhone"};

        int[] phoneIndices = {0,1,2}; //Default order

        int minIndex = 0;

        int maxIndex = phoneNums.Length - 1;

        //Assign index for missing to last and preferred to first

        for (int i = 0; i<3 ; i++)

        {

            if (String.IsNullOrEmpty(phoneNums[i]))

            {

                phoneIndices[i] = maxIndex;

                maxIndex--;

            }

            else if (phoneTypes[i] == phoneTypePref){

                phoneIndices[i] = minIndex;

                minIndex++;

            }

        }

        //Then assign index for the rest

        for (int j = 0; j<3 ; j++)

        {

            if ((phoneTypes[j] != phoneTypePref) && !String.IsNullOrEmpty(phoneNums[j])){

                phoneIndices[j] = minIndex;

                minIndex++;

            }

        }       

        return phoneIndices[Array.IndexOf(phoneTypes,phoneType)];

    }

        static int getPhoneIndex(string phoneTypePref, string homePhone, string cellPhone, string workPhone, string phoneType)

        {

            var phone = new Dictionary<string, string>()

            {

                { "HomePhone", homePhone },

                { "CellPhone", cellPhone },

                { "WorkPhone", workPhone }

            };

            var phoneList = new List<KeyValuePair<string, string>>();

            var emptyNumbers = new List<KeyValuePair<string, string>>();

​

            //Assign index for missing to last and preferred to first

            foreach (KeyValuePair<string, string> pair in phone)

            {

                if (string.IsNullOrEmpty(pair.Value))

                {

                    emptyNumbers.Add(pair);

                }

                else if (pair.Key == phoneTypePref)

                {

                    phoneList.Insert(0, pair);

                }

                else

                {

                    phoneList.Add(pair);

                }

            }

​

            if (emptyNumbers.Count > 0)

            {

                phoneList.AddRange(emptyNumbers);

            }

​

            return phoneList.IndexOf(phoneList.Where(a => a.Key == phoneType).FirstOrDefault());

        }

}