using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    class A

    {

        public int Index { get; set; }

        public bool State { get; set; }

    }

    public static void Main()

    {

        List<A> list1 = new List<A>() {

            new A(){ Index = 1, State = false },

            new A(){ Index = 2, State = false },

            new A(){ Index = 3, State = true },

            new A(){ Index = 4, State = false },

            new A(){ Index = 5, State = false },

        };

        List<A> list2 = new List<A>() {

            new A(){ Index = 1, State = false },

            new A(){ Index = 2, State = true },

            new A(){ Index = 3, State = false },

            new A(){ Index = 4, State = false },

            new A(){ Index = 5, State = false },

            new A(){ Index = 6, State = true },

            new A(){ Index = 7, State = false },

        };

        var left = (from l1 in list1

                          join l2 in list2 on l1.Index equals l2.Index into j

                          from l2 in j.DefaultIfEmpty()

                          select new A()

                          {

                              Index = l1.Index,

                              State = l1.State | (l2 == null ? false : l2.State)

                          }

                         );

​

        var right = (from l2 in list2

                          join l1 in list1 on l2.Index equals l1.Index into k

                          from l1 in k.DefaultIfEmpty()

                          select new A()

                          {

                              Index = l2.Index,

                              State = l2.State | (l1 == null ? false : l1.State)

                          }

                         );

​

        Dictionary<int, A> dict = left.Union(right).GroupBy(x => x.Index).Select(x => x.First())

            .ToDictionary(x => x.Index, y => y);

        foreach (A item in left)

        {

            Console.WriteLine("{0} {1}", item.Index, item.State);

        }

        Console.WriteLine();

        foreach (A item in right)

        {

            Console.WriteLine("{0} {1}", item.Index, item.State);

        }

        Console.WriteLine();

        foreach (int key in dict.Keys)

        {

            Console.WriteLine("{0} {1}", key, dict[key].State);

        }

​

    }

}