using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace ConsoleApplication1

{

    public enum Field {

        one, two, three, four

    }

    class Item

    {

        public DateTime Date { get; set; }

        public int Amount { get; set; }

        public Field FieldGain { get; set; }

    }

​

    public class Program

    {

        public static void Main(string[] args)

        {

            List<Item> list = new List<Item>() { 

                new Item() { Date = DateTime.Now.AddDays(-1) , Amount = 12,   FieldGain = Field.one   },

                new Item() { Date = DateTime.Now.AddDays(-1) , Amount = 6,    FieldGain = Field.one   },

                new Item() { Date = DateTime.Now.AddDays(-2) , Amount = 12,   FieldGain = Field.two   },

                new Item() { Date = DateTime.Now.AddDays(-2) , Amount = 12,   FieldGain = Field.two   },

                new Item() { Date = DateTime.Now.AddDays(-3) , Amount = 8,    FieldGain = Field.one   },

                new Item() { Date = DateTime.Now.AddDays(-3) , Amount = 12,   FieldGain = Field.three },

                new Item() { Date = DateTime.Now.AddDays(-4) , Amount = 1,    FieldGain = Field.two   },

                new Item() { Date = DateTime.Now.AddDays(-15) , Amount = 102, FieldGain = Field.one   },

            };

​

            var result_set =

                list

                .OrderBy(x => x.FieldGain)

                .GroupBy(x => x.FieldGain)

                .ToDictionary(x => x.Key, x => new {

                    begin     = x.ToList().Min(Item => Item.Date),

                    end       = x.ToList().Min(Item => Item.Date),

                    SumAmount = x.ToList().Sum(Item => Item.Amount)

                })

                .ToList();

            int progess = 0;

            result_set.ForEach(x => {

                Console.WriteLine("+" +

                    x.Value.SumAmount +

                    "\t" +

                    " progress : " +

                    (progess =  progess + x.Value.SumAmount) +

                    " (" + 

                    x.Value.begin + 

                    x.Value.end + 

                    ")" +

                    x.Key

                );

                }

            );

        }

    }

}