C# 合併只要有交集的所有集合

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 
  7 namespace ConsoleApplication2
  8 {
  9     class Program
 10     {
 11         static void Main(string[] args)
 12         {
 13 
 14             List<int> list1 = new List<int> { 1, 2, 3 };
 15             List<int> list2 = new List<int> { 4, 5, 6 };
 16             List<int> list3 = new List<int> { 1, 4, 7 };
 17 
 18 
 19             List<int> list4 = new List<int> { 10, 11, 12 };
 20             List<int> list5 = new List<int> { 13, 11, 14 };
 21 
 22 
 23             List<int> list6 = new List<int> { 16, 17, 18 };
 24             List<int> list7 = new List<int> { 18, 19, 20 };
 25 
 26             List<List<int>> list = new List<List<int>>();
 27             list.Add(list1);
 28             list.Add(list2);
 29             list.Add(list3);
 30             list.Add(list4);
 31             list.Add(list5);
 32             list.Add(list6);
 33             list.Add(list7);
 34 
 35             List<int> allint = new List<int>();//所有的集合數據
 36             HashSet<int> repeated = new HashSet<int>(); //得到沒有重覆的hashset
 37             foreach (List<int> item in list)
 38             {
 39                 foreach (int index in item)
 40                 {
 41                     if (allint.Contains(index))
 42                         repeated.Add(index);//得到所有重覆的集合的元素
 43                     allint.Add(index);//得到所有的集合的元素
 44                 }
 45             }
 46 
 47 
 48             foreach (var setkey in repeated)//迴圈重覆的值
 49             {
 50                 List<int> templist = null;//臨時
 51                 List<List<int>> removelist = new List<List<int>>();
 52                 foreach (var item in list)//迴圈
 53                 {
 54                     //if (templist == null)
 55                     //{
 56                     //    templist = item;
 57                     //    removelist.Add(item);
 58                     //}
 59 
 60                     //if (item.Contains(setkey))
 61                     //{
 62                     //    removelist.Add(item);
 63                     //    templist = templist.Union(item).ToList();
 64                     //}
 65 
 66                     if (item.Contains(setkey))
 67                     {
 68                         if (templist == null)
 69                         {
 70                             templist = item;
 71                             removelist.Add(item);
 72                         }
 73                         else
 74                         {
 75                             removelist.Add(item);
 76                             templist = templist.Union(item).ToList();
 77                         }
 78                     }
 79                 }
 80                 foreach (var item in removelist)
 81                 {
 82                     list.Remove(item);
 83                 }
 84                 removelist.Clear();
 85                 list.Add(templist);
 86             }
 87 
 88             foreach (var item in list)
 89             {
 90                 foreach (var item1 in item)
 91                 {
 92                     Console.Write(item1 + " , ");
 93                 }
 94                 Console.Write("\r\n");
 95             }
 96             Console.ReadKey();
 97         }
 98 
 99 
100     }
101 }