从列表 C# 中获取对象对的最佳方法

Question

I have a List of objects named Team and I want the optimal way to get all the possible pairs of objects. I've written an example:

public void GenerateMatches(Team team)
    {

        for(int i = 0; i < team.Count-1; i++)
        {
            for (int j = i + 1; j < team.Count; j++)
            {
                Console.WriteLine("Match:" + team[i].Name + " vs " + team[j].Name);
            }
        }
    }

This is far from optimal but it works. Any better ideas?

Answer 1

Here is the solution :

You will need to iterate Teams and take pairs of currentTeam with all the next indexes:

    List<int> MyList = new List<int> {1, 2, 3, 4, 5, 6, 7, 8, 9}; // sample input

    List<KeyValuePair<int, int>> MyPairs = new List<KeyValuePair<int, int>>(); // prepare final result

    for (int i = 0; i < MyList.Count; i++)
        for (int j = i + 1; j < MyList.Count; j++)
            if(j < MyList.Count)
                MyPairs.Add(new KeyValuePair<int, int> (MyList[i], MyList[j]));

Then to display :

    foreach (var pair in MyPairs)
        Console.WriteLine(pair.Key +" vs "+ pair.Value);

Part of the output :

Answer 2

The optimal running time is n(n - 1)/2 , since this is the number of ordered pairs.
Your solution is optimal.