using System;

public class Program

{

    const string INVALID_SCORE = "ERROR: Invalid game points specified";

    const string SERVER = "Server";

    const string RECIEVER = "Receiver";

    static string PointName(int Point)

    {

        switch(Point)

        {

            case 0: return "Love";

            case 1: return "15";

            case 2: return "30";

            case 3: return "40";

            default: return "<ERROR>";

        }

    }

    public static string TennisGameScore(int servingPlayerPoints, int recievingPlayerPoints)

    {

        //The logic for creating the tennis score should be as follows:

        //The names to use for the players are:

        //servingPlayerPoints = 'Server'

        //recievingPlayerPoints = Receiver'

        //The names for points 0-3 are as follow:

        //0: Love

        //1: 15

        //2: 30

        //3: 40

        //For a player to win a game, they must have:

        //* More than 3 points AND

        //* They must have 2 more points than their opponent

        //IF a player has won the game, the string returned should just be the name of the winner followed by ' Won!'

        //ELSE If both players have less then 4 points and both players have a different number of points:

        //then return the name of each of their points seperated by ' - '. Server first, then reciever

        //ELSE If both players have less than 4 points and both players have the same number of points:

        //then return the name for those number of points followed by ' all'

        //ELSE If both players have 4 or more points and both players have the same number of points:

        //then return '40 all'

        //ELSE return 'Advantage ' followed by the name of the player with more points

        //BONUS TEST

        //If a number of points is passed in that should be impossible, return "ERROR: Invalid game points specified";

        //Negative point values are already handled.

        //But another way to have an invalid score is where one player has more points than they could possibly achieve because

        //the game would have already been won at an earlier point...

        if(servingPlayerPoints < 0 || recievingPlayerPoints < 0)

        {

            return INVALID_SCORE;

        }

        string serverPoints = PointName(servingPlayerPoints);

        string receivingPoints = PointName(recievingPlayerPoints);

        //Check if a player has won

        if(servingPlayerPoints > 3 || recievingPlayerPoints > 3)

        {

            if(servingPlayerPoints - recievingPlayerPoints == 2) return SERVER + " Won!";

            else if(recievingPlayerPoints - servingPlayerPoints == 2) return RECIEVER + " Won!";

            //Has either side won by a number greater than 2?

            if(servingPlayerPoints - recievingPlayerPoints >= 2)

            {

                //Only allowed if the winner has only 4 points exactly

                if(servingPlayerPoints == 4) return SERVER + " Won!";

                else return INVALID_SCORE;

            }

            if(recievingPlayerPoints - servingPlayerPoints >= 2)

            {

                //Only allowed if the winner has only 4 points exactly

                if(recievingPlayerPoints == 4) return RECIEVER + " Won!";

                else return INVALID_SCORE;

            }

        }

        if(servingPlayerPoints <= 3 && recievingPlayerPoints <= 3)

        {

            if(servingPlayerPoints == recievingPlayerPoints) return serverPoints + " all";

            else return serverPoints + " - " + receivingPoints;

        }

        else if(servingPlayerPoints == recievingPlayerPoints)

        {

            return "40 all";

        }

        else if(servingPlayerPoints > recievingPlayerPoints)

        {

            return "Advantage " + SERVER;

        }

        else

        {

            return "Advantage " + RECIEVER;

        }

    }

    /*** DO NOT EDIT BELOW THIS LINE ***/

    public static void Main()

    {

        TestTennisScore(0, 0);  //'Love all'

        TestTennisScore(0, 2);  //'Love - 30'

        TestTennisScore(1, 0);  //'15 - Love'

        TestTennisScore(3, 1);  //'40 - 15'

        TestTennisScore(4, 1);  //'Server Won!'

        TestTennisScore(0, 4);  //'Receiver Won!'

        TestTennisScore(2, 2);  //'30 all'

        TestTennisScore(3, 3);  //'40 all'

        TestTennisScore(6, 6);  //'40 all'

        TestTennisScore(10, 10); //'40 all'

        TestTennisScore(4, 3);  //'Advantage Server'

        TestTennisScore(6, 7);  //'Advantage Receiver'

        TestTennisScore(6, 8);  //'Receiver Won!'

        TestTennisScore(12, 10); //'Server Won!'

​

        //BONUS - 'Impossible scores'

        //The result shown by each test below is an 'acceptable' answer

        //But the ideal, bonus answer for all below tests should be:

        //'ERROR: Invalid game points specified'

        Console.WriteLine("");

        Console.WriteLine("***BONUS TESTS***");

        TestTennisScore(6, 0);  // 'Server Won!'

        TestTennisScore(2, 7);  // 'Reciever Won!'

        TestTennisScore(5, 1);  // 'Server Won!'

        TestTennisScore(5, 13); // 'Reciever Won!'

    }

    static void TestTennisScore(int servingPlayerPoints, int recievingPlayerPoints)

    {

        Console.WriteLine(servingPlayerPoints + ", " + recievingPlayerPoints + " = " + TennisGameScore(servingPlayerPoints, recievingPlayerPoints));

    }

}