📅  最后修改于: 2022-03-11 14:49:14.639000             🧑  作者: Mango
using System.Linq;
public class Program
{
public static int DuplicateCount(string str)
{
return str.ToCharArray()
.GroupBy(x => x)
.Where(x => x.Count() > 1)
.Count();
}
}