c# - 给定排序字符串的游程编码

Question

Write code for run -length encoding of a given string
Sample Input: aaaaaaaaaabcccccc
Output: a10bc6

我的代码:

static void Main(string[] args)
{
    string str = "aaaaaaaaaabcccccc";
    var qry = (from c in str
               group c by c into grp
               select new
               {
                   output = grp.Key.ToString() + grp.Count().ToString()
               });
    StringBuilder sb = new StringBuilder();
    foreach (var item in qry)
    {
        sb.Append(item.output);
    }
    Console.WriteLine(sb.ToString());
    Console.ReadLine();
}

然而它返回:

a10b1c6

我想删除非重复字符的计数，这里是字母“b”的“1”。

假设它是一个排序的字符串。

Answer 1

添加一个三元表达式:

output = grp.Key + (grp.Count() > 1 ? grp.Count().ToString() : "")