string 去重复

//AABB>>AB         //AAA>>A         //ABBAA>ABA

public static string SpiltString(string str)         {

List<char> lstr = new List<char>();

for (int i = 0; i < str.Length; i++)

{                 //第一项添加 从第二项开始比较

if (i == 0)

{

lstr.Add(str[i]);

}

else if (str[i] != str[i - 1])

{

lstr.Add(str[i]);

}

}

string st = "";

foreach (char i in lstr)

{

st += i.ToString();

}

return st;

}