通过计算获得一个使用最少量充值卡满足充值额度的方案

类似于找一定数目的钱，使用最少的钱数达到效果，凑钱问题

　　

/************************************
 * author:lijia
 * date:2016-04-20
 * description:通过计算获得一个使用最少
 * 量充值卡满足充值额度的方案
 * **********************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CountMoney
{
    class Counter
    {
        /// <summary>
        /// 总钱数
        /// </summary>
        private int money;

        /// <summary>
        /// 面额选择
        /// </summary>
        private int[] choice;
        
        /// <summary>
        /// 选择的面额
        /// </summary>
        private List<int> needType = new List<int>();
        
        /// <summary>
        /// 各面额需要数目的结果
        /// </summary>
        public Dictionary<int, int> dicResult = new Dictionary<int, int>();
        
        /// <summary>
        /// 构造函数，初始化参数
        /// </summary>
        /// <param name="money"></param>
        /// <param name="choice"></param>
        public Counter(string money, int[] choice)
        {
            this.money = int.Parse(money);
            this.choice = choice.ToArray().OrderBy(p => p).Reverse().ToArray();            
        }

        /// <summary>
        /// 计算结果
        /// </summary>
        public void CountResult()
        {
            if (this.choice.Length > 0)
            {
                HandleNeedType(money);              

                foreach (int i in needType)
                {
                    if(i != 0)
                    {
                        int num = money / i;
                        money = money % i;
                        dicResult.Add(i, num);
                        //result += string.Format("面额{0}需要数目为{1}  ",i,num);
                    }
                    
                }
            }
           
        }

        /// <summary>
        /// 需要面额类型
        /// </summary>
        /// <param name="remain">剩余金额</param>
        /// <returns>面额类型</returns>
        private int GetNeedType(int remain)
        {
            foreach (var i in choice)
            {
                if (remain >= i)
                {
                    return i;                    
                }
            }
            return 0;
        }

        /// <summary>
        /// 通过计算得到需要的面额种类，添加到list中
        /// </summary>
        /// <param name="remainMoney">剩余金额</param>
        private void HandleNeedType(int remainMoney)
        {
            var need = GetNeedType(remainMoney);
            if (need != 0)
            {
                needType.Add(need);
                var remain = remainMoney % need;
                if (remain > 0)
                {
                    HandleNeedType(remain);
                }                
            }
            else
            {
                needType.Add(0);//如果没有最小的可用面额，添加0作为标记
            }
        }

    }
}