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

namespace BeiBao{    public class Program    {        static void Main(string[] args)        {            Goods goods = new Goods()            {                LimitWeight = 3,                LimitNum = 4,                Weight = new double[4] { 1, 1, 1, 1 },                Value = new double[4] { 12, 3, 10, 25 }            };

            BackPack(goods, 0, 0, goods.Value.Sum());

            Console.WriteLine("经过最优化求解：\n");

            for (int i = 0; i < goods.Selected.Length; i++)            {                if (goods.Selected[i])                {                    Console.WriteLine("重量：" + goods.Weight[i] + " 价值：" + goods.Value[i]);                }            }

            Console.Read();        }

        static double maxValue;

        static bool[] selected = new bool[4];

        static void BackPack(Goods good, int i, double tw, double tv)        {            //当前追加物品的重量            var currentWeight = tw + good.Weight[i];

            //当前重量小于限制重量则继续追加            if (currentWeight <= good.LimitWeight)            {                selected[i] = true;

                //如果当前不是最后一个商品，则继续追加                if (i < good.LimitNum - 1)                {                    BackPack(good, i + 1, tw + good.Weight[i], tv);                }                else                {                    for (int k = 0; k < good.LimitNum; k++)                    {                        good.Selected[k] = selected[k];                    }                    maxValue = tv;                }            }

            selected[i] = false;

            //这里就体现了动态规划的根本目的，解决冗余            if (tv - good.Value[i] > maxValue)            {                if (i < good.LimitNum - 1)                {                    //排除当前物品所剩余的价值总值                    var exceptNotSelectedValue = tv - good.Value[i];

                    BackPack(good, i + 1, tw, exceptNotSelectedValue);                }                else                {                    for (int k = 0; k < good.LimitNum; k++)                    {                        good.Selected[k] = selected[k];                    }

                    maxValue = tv - good.Value[i];                }            }        }    }

    #region 商品的实体    /// <summary>    /// 商品的实体    /// </summary>    public class Goods    {        public double[] Value = new double[4];        public double[] Weight = new double[4];        public bool[] Selected = new bool[4];        public int LimitNum { get; set; }        public double LimitWeight { get; set; }    }    #endregion}