What data structures can I use to represent a strongly-typed 2D matrix of data in .Net?

Question

I'm trying to represent a scoreboard for a competition and am struggling with the best data structures to use.

I have a list of Player objects, a list of Round objects, and for each combination, I need to store a RoundScore object (there are various parts to the score for a round).

What I'd like is some overall Scoreboard object where the following holds:

1 - I can access a collection of RoundScore objects identified by Round keys by providing a Player object. For example, maybe something like:

public IDictionary<Round,RoundScore> PlayerScores(Player player) { ... }

2 - I can access a collection of RoundScore objects identified by Player keys by providing a Round object. e.g:

public IDictionary<Player,RoundScore> RoundScores(Round round) { ... }

3 - I can access a single RoundScore object by providing a Player and a Round

4 - I can add a new Round and all Players will get a new RoundScore for that round with default values

5 - Similarly, I can add a new Player and all Rounds will have a new RoundScore for that player with default values

---

I guess what I'm really looking for is a representation of a grid with Rounds on one axis, Players on the other, and RoundScores in the middle.

Is there any data structure (or combination of data structures) already in .Net that I can use for this or will I have to roll my own?

Answer 1

Why not model this the object oriented way?

Competition
-Games
--Game01
---Players
---Rounds
----Round1
-----Score
----Round2
-----Score
---Score (Game)

Another way to do this would be an ordinary array. For more on .Net colectios see http://dotnetperls.com/collections.

Answer 2

I believe you'll have to roll your own. You could store your matrix of data in one of these:

List<List<RoundScore>>

Then in Round, add a field that stores the index of that Round's scores. Likewise, in Player, add a field for that player's scores.

If the rows are the scores for a round, then returning that list is trivial. To return the list of scores for a player, you could create a class that implements IList, which knows how to access the scores by index. By doing this, you don't have to copy the scores into a new list each time they are requested.

For example:

List<Player> Players;
List<Round> Rounds;
List<List<RoundScore>> Scores;


List<RoundScore> GetRoundScores(Round round)
{
    return Scores[round.Index];
}

IList<RoundScore> GetRoundScores(Player player)
{
    return new PlayerScoreList(Scores, player.Index); // or better yet, cache this
}


public class PlayerScoreList : IList<RoundScore>
{
    private List<List<RoundScore>> _scores;
    private int _playerIndex;

    public RoundScore this[int index]
    {
        get
        {
            return _scores[_playerIndex][index];
        }
        set
        {
            _scores[_playerIndex][index] = value;
        }
    }

    public PlayerScoreList(List<List<RoundScore>> scores, int playerIndex)
    {
        _scores = scores;
        _playerIndex = playerIndex;
    }

    public void Add(RoundScore item)
    {
        throw new NotSupportedException();
    }

    public void Clear()
    {
        throw new NotSupportedException();
    }

    public bool Contains(RoundScore item)
    {            
        for (int i = 0; i < Count; i++)
        {
            if (this[i].Equals(item))
            {
                return true;
            }
        }

        return false;
    }

    public int Count
    {
        get { return _scores[0].Count; }
    }

    public IEnumerator<RoundScore> GetEnumerator()
    {
        for (int i = 0; i < Count; i++)
        {
            yield return this[i];
        }
    }

    // ... more methods

}