leetcode557

    public class Solution
    {
        public string ReverseWords(string s)
        {
            var list = s.Split(' ').AsEnumerable().ToList();//用空格将单词分隔开

            for (int i = 0; i < list.Count(); i++)//循环每一个单词
            {
                var str = list[i];
                var chars = str.Reverse();//将这个单词反转

                StringBuilder sb = new StringBuilder();

                foreach (var c in chars)
                {
                    sb.Append(c);
                }
                list[i] = sb.ToString();//存储反转后的单词
            }

            StringBuilder sb2 = new StringBuilder();

            foreach (var str in list)//拼接单词
            {
                sb2.Append(str);
                sb2.Append(" ");
            }

            var result = sb2.ToString().Substring(0, sb2.Length - 1);//消去最后的一个空格

            //Console.WriteLine(result);

            return result;
        }
    }

https://leetcode.com/problems/reverse-words-in-a-string-iii/#/description