/// <summary>
/// 算法：
/// 1.每个项权重+1命名为w，防止为0情况。
/// 2.计算出总权重n。
/// 3.每个项权重w加上从0到(n-1)的一个随机数（即总权重以内的随机数），得到新的权重排序值s。
/// 4.根据得到新的权重排序值s进行排序，取前面s最大几个。
/// </summary>
/// <param name="list">原始列表</param>
/// <param name="count">随机抽取条数</param>
/// <returns></returns>
public List <tblSubroute> GetRandomList(List <tblSubroute> list, int count)
{
if (list == null || list.Count <= count || count <= 0)
{
return(list);
}
//计算权重总和
int totalWeights = 0;
for (int i = 0; i < list.Count; i++)
{
totalWeights += int.Parse(list[i].fldWeight) + 1; //权重+1，防止为0情况。
}
//随机赋值权重
Random ran = new Random(GetRandomSeed()); //GetRandomSeed()随机种子，防止快速频繁调用导致随机一样的问题
List <KeyValuePair <int, int> > wlist = new List <KeyValuePair <int, int> >(); //第一个int为list下标索引、第一个int为权重排序值
for (int i = 0; i < list.Count; i++)
{
int w = int.Parse(list[i].fldWeight) + ran.Next(0, totalWeights); // （权重+1） + 从0到（总权重-1）的随机数
wlist.Add(new KeyValuePair <int, int>(i, w));
}
//排序
wlist.Sort(
delegate(KeyValuePair <int, int> kvp1, KeyValuePair <int, int> kvp2)
{
return(kvp2.Value - kvp1.Value);
});
//根据实际情况取排在最前面的几个
List <tblSubroute> newList = new List <tblSubroute>();
for (int i = 0; i < count; i++)
{
tblSubroute entiy = list[wlist[i].Key];
newList.Add(entiy);
}
//随机法则
return(newList);
}
public HttpResponseMessage UpdateSubroute(uppram reparm)
{
string result = string.Empty;
try
{
using (YYPlayContext yYPlay = new YYPlayContext())
{
tblSubroute tbls = (from x in yYPlay.tblSubroute
where x.fldAutoID == reparm.fldAutoID
select x).FirstOrDefault();
tbls.fldState = reparm.fldState == "0" ? false : true;
tbls.fldWeight = reparm.fldWeight;
tbls.fldMinmoney = reparm.fldMinmoney;
tbls.fldMaxmoney = reparm.fldMaxmoney;
tbls.fldProhibitMerchant = reparm.fldProhibitMerchant;
int i = yYPlay.SaveChanges();
if (i > 0)
{
result = rule.JsonStr("ok", "成功", i);
}
else
{
result = rule.JsonStr("error", "失败", i);
}
}
}
catch (Exception e)
{
//错误保存日志
throw new InsertException(e.Message, "Subroute", "GetSubroute", "");
}
return(new HttpResponseMessage {
Content = new StringContent(result, System.Text.Encoding.UTF8, "application/json")
});
}
