c#环境下，一个数据结构的问题该如何编程

Question

如图所示：
C#环境下
同一行表示“相互联通”
输入为左边一列，和右边一列，比如左边为 str1［］＝{“A”，“A”，“C”，“E”，“F”}
最后结果把所有联通的归到一起，
所以输出应当为{{“A”，“B”，“C”，“D”}，{“E”，“F”，“G”} }
这个该如何编程？

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string[] str1 = { "A", "A", "C", "E", "F" };
            string[] str2 = { "B", "C", "D", "F", "G" };
            int[] re = { 1, 0, 0, 0, 0, };
            int index = 2;
            for (int i = 1; i < str1.Length; i++)
            {
                int st = 0;
                for (int j = 0; j <= i-1; j++)
                {
                    if((str1[i]==str1[j]) || (str2[i]==str1[j]) || (str1[i] == str2[j]) || (str2[i]==str2[j]))
                    {
                        re[i] = re[j];
                        st = 1;
                        break;
                    }
                }
                if (st == 0)
                {
                    re[i] = index;
                    index++;
                }
            }
            List<List<string>> res= new List<List<string>>();
            for (int i = 0; i < index-1; i++)
            {
                res.Add(new List<string>());
            }
            for (int i = 0; i < str1.Length; i++)
            {
                if (!res[re[i]-1].Contains(str1[i]))
                {
                    res[re[i] - 1].Add(str1[i]);
                }
                if (!res[re[i] - 1].Contains(str2[i]))
                {
                    res[re[i] - 1].Add(str2[i]);
                }
                    
            }
            Console.Write("{");
            for (int i = 0; i < res.Count; i++)
            {
                Console.Write("{");
                for (int j = 0; j < res[i].Count; j++)
                {
                    Console.Write(res[i][j]);
                    if (j==res[i].Count-1)
                    {
                        break;
                    }
                    Console.Write(",");
                }
                
                if (i==res.Count-1)
                {
                    Console.Write("}");
                }
                else
                {
                    Console.Write("},");
                }
            }
            Console.Write('}');
            Console.ReadKey();
        }
    }
}