题解 | #找出字符串中第一个只出现一次的字符#

using System;
using System.Linq;

namespace HJ59
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string inputStr = Console.ReadLine();
            var chars = inputStr.Where(c => inputStr.Count(x => x == c) == 1);
            if (chars.Any())
            {
                Console.WriteLine(chars.ElementAt(0));
                return;
            }
            Console.WriteLine(-1);
        }
    }
}