C#의 하위 문자열

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; public class Demo { public bool CheckUnique(string str) { string one = ""; string two = ""; for (int i = 0; i < str.Length; i++) { one = str.Substring(i, 1); for (int j = 0; j < str.Length; j++) { two = str.Substring(j, 1); if ((one == two) && (i != j)) return false; } } return true; } static void Main(string[] args) { Demo d = new Demo(); bool b = d.CheckUnique("amit"); Console.WriteLine(b); Console.ReadKey(); } }