排序（7）归并排序

6.归并排序:

将两个有序表合并为一个有序表.

	/// <summary>
	/// 归并排序.
	/// </summary>
	public void SortMethod7()
	{
		recNum = 0;
		int count = m_playerList.Count;
		int k = 1;
		while(k < count)
		{
			Merge(k,count);
			k*=2;
		}
		OutPutMsg();
	}
	void Merge(int len,int count)
	{
		int m = 0;
		int s1 = 0;
		int e1 = 0;
		int s2 = 0;
		int e2 = 0;
		int i = 0;
		int j = 0;
		List<Player> temps = new List<Player>();
		while(s1 + len < count)
		{
			s2 = s1 + len;
			e1 = s2 - 1;
			e2 = (s2 + len -1) < count ? (s2 + len -1):count;
			j = s2;
			i = s1;
			
			while(i <= e1 && j <= e2)
			{
				if(m_playerList[i].level >= m_playerList[j].level)
				{
					temps.Add(m_playerList[i++]);
				}
				else
				{
					temps.Add(m_playerList[j++]);
				}			
			}
			while(i <= e1)
			{
				temps.Add(m_playerList[i++]);
			}
			while (j <= e2)
			{
				temps.Add(m_playerList[j++]);
			}
			s1 = e2 + 1;
		}
		i = s1;
		while(i < count)
		{
			temps.Add(m_playerList[i++]);
		}
		for(i = 0;i < count;i++ )
		{
			m_playerList[i] = temps[i];
		}
	}

归并排序时间复杂度：0（nlog2n） ,空间复杂度：0（n）这个主要是temps临时存放了。

这个排序也理解了，就是一下不能马上写出来。