namespace Juxiantang
{
    public static class CollectionOperate
    {
        /// <summary>
        /// 对两个已排序的集合进行分解合并操作
        /// a中独有的存放在c.A中
        /// a,b都有的存放在c.AB中
        /// b中独有的存放在c.B中
        /// </summary>
        /// <typeparam name="T">必须是可以比较的类型</typeparam>
        /// <param name="a">集合a</param>
        /// <param name="b">集合b</param>
        /// <returns>返回c(A, AB, B)</returns>
        public static ThreeCollection<T> BreakUpSortedCollection<T>(IEnumerable<T> a, IEnumerable<T> b)
            where T : IComparable<T>
        {
            IEnumerator<T> ia = a.GetEnumerator();
            IEnumerator<T> ib = b.GetEnumerator();
            ThreeCollection<T> c = new ThreeCollection<T>();
            if (!ia.MoveNext()) //a集合为空
            {
                c.B.AddRange(b);
                return c;
            }
            if (!ib.MoveNext()) //b集合为空
            {
                c.A.AddRange(a);
                return c;
            }
            
            ia.Reset();
            ib.Reset();
            ia.MoveNext();
            ib.MoveNext();
            Lookup<T>(ia, ib, c.A, c.AB, c.B);
            return c;
        }

/// <summary>
        /// 针对集合a的当前值a.Current，对比集合b的当前值b.Current
        /// 根据对比情况将a.Current或b.Current放入A, AB, B中
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="ia"></param>
        /// <param name="ib"></param>
        /// <param name="A"></param>
        /// <param name="AB"></param>
        /// <param name="B"></param>
        private static void Lookup<T>(IEnumerator<T> ia, IEnumerator<T> ib, List<T> A, List<T> AB, List<T> B)
            where T : IComparable<T>
        {
            int compareResult = (ia.Current.CompareTo(ib.Current));
            if (compareResult < 0) //a.Current < b.Current
            {
                A.Add(ia.Current);
                if (ia.MoveNext())
                {
                    Lookup<T>(ia, ib, A, AB, B);
                }
                else
                {
                    do
                    {
                        B.Add(ib.Current);
                    } while (ib.MoveNext());
                }
            }
            else if (compareResult == 0) //a.Current == b.Current
            {
                AB.Add(ia.Current);
                if (!ia.MoveNext())
                {
                    while (ib.MoveNext())
                    {
                        B.Add(ib.Current);
                    }
                }
                else if (ib.MoveNext())
                {
                    Lookup<T>(ia, ib, A, AB, B);
                }
            }
            else // a.Current > b.Current
            {
                B.Add(ib.Current);
                if (ib.MoveNext())
                {
                    Lookup<T>(ib, ia, B, AB, A);
                }
                else
                {
                    do
                    {
                        A.Add(ia.Current);
                    } while (ia.MoveNext());
                }
            }
        }
    }

/// <summary>
    /// 简单将A, AB, B集合在一起的实体
    /// </summary>
    /// <typeparam name="T">泛型</typeparam>
    public class ThreeCollection<T>
    {
        List<T> a = new List<T>();
        List<T> ab = new List<T>();
        List<T> b = new List<T>();

public List<T> B
        {
            get { return b; }
            set { b = value; }
        }

public List<T> AB
        {
            get { return ab; }
            set { ab = value; }
        }

public List<T> A
        {
            get { return a; }
            set { a = value; }
        }
    }

public class Program
    {
        static void Main()
        {
            int[] b = { 1, 2, 3, 4, 5, 6 };
            int[] a = { 8, 10, 11 };
            ThreeCollection<int> c = CollectionOperate.BreakUpSortedCollection<int>(a, b);
            System.Console.Write("A = ");
            Print<int>(c.A);
            System.Console.Write("AB = ");
            Print<int>(c.AB);
            System.Console.Write("B = ");
            Print<int>(c.B);
            System.Console.ReadLine();
        }

static void Print<T>(IEnumerable<T> list) where T : IFormattable
        {
            foreach (T o in list)
            {
                System.Console.Write(o.ToString());
                System.Console.Write(" ");
            }
            System.Console.Write("\n");
        }
    }
}