给定n个多种颜色的球，如何将球分组，保证每组内球颜色不能相同，且分组的数量要最小。

using System;
using System.Collections.Generic;

public class BallColorGroup
{
    public int Color { get; set; }
    public int Count { get; set; }
}

public class BallColorGrouping
{
    public static List<List<int>> GroupBalls(List<int> colors)
    {
        Dictionary<int, int> colorCount = new Dictionary<int, int>();

        // 统计每种颜色球的数量
        foreach (int color in colors)
        {
            if (!colorCount.ContainsKey(color))
            {
                colorCount[color] = 0;
            }
            colorCount[color]++;
        }

        List<List<int>> groups = new List<List<int>>();

        // 对颜色球按照数量由多到少进行排序
        var sortedColors = colorCount.Keys;
        Array.Sort(sortedColors.ToArray(), ((a, b) => colorCount[b].CompareTo(colorCount[a])));

        foreach (int color in sortedColors)
        {
            int count = colorCount[color];

            // 在现有分组里查找能放置当前颜色的分组
            bool groupFound = false;
            foreach (List<int> group in groups)
            {
                // 检查分组中是否有相同颜色的球
                if (!group.Contains(color))
                {
                    group.Add(color);
                    count--;
                    groupFound = true;
                    break;
                }
            }

            // 如果找不到能放置当前颜色的分组，则创建新的分组
            if (!groupFound)
            {
                List<int> newGroup = new List<int> { color };
                count--;
                groups.Add(newGroup);
            }

            // 将剩余颜色球加入新分组中
            while (count > 0)
            {
                List<int> newGroup = new List<int> { color };
                count--;
                groups.Add(newGroup);
            }
        }

        return groups;
    }

    public static void Main(string[] args)
    {
        List<int> ballColors = new List<int> { 1, 2, 1, 3, 2, 4, 5, 3, 5, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6 };

        List<List<int>> colorGroups = GroupBalls(ballColors);

        // 输出分组结果
        for (int i = 0; i < colorGroups.Count; i++)
        {
            Console.WriteLine($"Group {i + 1}: {string.Join(", ", colorGroups[i])}");
        }
    }
}