C#中的组合生成器

using System;
using System.Collections.Generic;

class CombinationGenerator
{
    public static List<List<T>> GenerateCombinations<T>(List<T> elements, int k)
    {
        List<List<T>> combinations = new List<List<T>>();
        GenerateCombinationsRecursive(elements, k, new List<T>(), combinations);
        return combinations;
    }

    private static void GenerateCombinationsRecursive<T>(List<T> elements, int k, List<T> currentCombination, List<List<T>> combinations)
    {
        if (k == 0)
        {
            combinations.Add(new List<T>(currentCombination));
            return;
        }

        for (int i = 0; i < elements.Count; i++)
        {
            currentCombination.Add(elements[i]);
            GenerateCombinationsRecursive(elements.GetRange(i + 1, elements.Count - i - 1), k - 1, currentCombination, combinations);
            currentCombination.RemoveAt(currentCombination.Count - 1);
        }
    }
}

class Program
{
    static void Main(string[] args)
    {
        List<int> elements = new List<int> { 1, 2, 3, 4 };
        int k = 2;

        List<List<int>> combinations = CombinationGenerator.GenerateCombinations(elements, k);

        foreach (List<int> combination in combinations)
        {
            Console.WriteLine(string.Join(", ", combination));
        }
    }
}

1, 2
1, 3
1, 4
2, 3
2, 4
3, 4