一直想比较一下查找算法，最近工作之余实现了一下算法，做了一下对比

现在有一链表

static ArrayList _serverList = new ArrayList();里面的数据为int,保证其值从小到大排列。当然，我们在写入数据时用查找算法找到相应位置写入就行了。

1：顺序比较，这个太土，就是一个一个比，这个我就不说了，也没有实现

2：折半居中查找，如果是10000000个数据，查找一次要节约0.2秒左右的时间

下面是程序

    public class ServerList
    {
        #region
        static ArrayList _serverList = new ArrayList();
        int leftFind = 0;
        int rightFind = 0;
        int serverIndex = -1;
        public ServerList()
        { }

        public bool AddServer(int serverId)
        {
            try
            {
                lock (_serverList)
                {
                    int iGetServer;
                    iGetServer = GetServer(serverId);
                    if (_serverList.Count == 0)
                        _serverList.Add(serverId);
                    else if (serverId == iGetServer)
                    {
                        return false;
                        //Console.WriteLine(“不能添加，已经有相同的Server”);
                    }
                    else if (serverId < (int)(_serverList[0]))
                        _serverList.Insert(0, serverId);
                    else if (serverId > (int)(_serverList[_serverList.Count – 1]))
                        _serverList.Insert(_serverList.Count, serverId);
                    else _serverList.Insert(serverIndex, serverId);
                }
            }
            catch
            {
                return false;
            }
            return true;
        }

        public bool DeleteServer(int serverId)
        {
            try
            {
                lock (_serverList)
                {
                    int iGetServer;
                    iGetServer = GetServer(serverId);
                    if (serverIndex >= 0)
                        _serverList.Remove(iGetServer);
                }
            }
            catch
            {
                return false;
            }
            return true;
        }

        public int GetServer(int serverId)
        {
            leftFind = 0;
            rightFind = _serverList.Count – 1;
            serverIndex = -1;
            if (_serverList.Count == 0)
                return -1;
            if (_serverList.Count == 1 || serverId == (int)(_serverList[0]))
            {
                serverIndex = 0;
                return (int)(_serverList[0]);
            }
            if (serverId < (int)(_serverList[0]) || serverId >= (int)(_serverList[_serverList.Count – 1]))
            {
                serverIndex = _serverList.Count – 1;
                return (int)(_serverList[_serverList.Count – 1]);
            }
            int iServerIndex = _serverList.Count / 2;
            return GetMax(iServerIndex, serverId);
        }

        internal int GetMax(int index, int serverId)
        {
            if ((int)(_serverList[index]) == serverId)
            {
                serverIndex = index;
                return (int)(_serverList[index]);
            }
            if (rightFind – leftFind <= 1)
            {
                serverIndex = rightFind;
                return (int)(_serverList[rightFind]);
            }
            if (serverId > (int)(_serverList[index]))
            {
                leftFind = index;
                index = index + (rightFind – index) / 2;
            }
            if (serverId < (int)(_serverList[index]))
            {
                rightFind = index;
                index = index – (index – leftFind) / 2;
            }
            return GetMax(index, serverId);
        }

        public string GetServerString()
        {
            if (_serverList.Count == 0)
                return “It not have any Server”;
            string strServerList = “”;
            for (int i = 0; i < _serverList.Count; i++)
            {
                strServerList += _serverList[i].ToString() + “,”;
            }
            strServerList = strServerList.Trim(new char[] { ‘,’ });
            return strServerList;
        }
        #endregion

    }