面试题目记录

面试题目1： 把一个段落中的日期格式字符串更改格式，由MM/DD/YYYY 更改为 DD/MM/YYYY

比如 输入语句为  "Last time it rained was on 07/25/2013 and today is 08/09/2013"  转换后的输出语句为  "Last time it rained was on 25/07/2013 and today is 09/08/2013"

方法： 采用正则表达式，把段落中的日期格式字符串替换

 static void Main(string[] args)
        {

            string newStr = UpdateDateFormat("Last time it rained was on 07/25/2013 and today is 08/09/2013");
            Console.WriteLine(newStr);
        }



        public static string UpdateDateFormat(string a)
        {

            string[] str1 = a.Split(' ');

            var pattern = @"(d+)/(d+)/(d+)";

            Regex rgx = new Regex(pattern, RegexOptions.None,TimeSpan.FromMilliseconds(150));

            foreach (var item in str1)
            {

                var newItem = "";

                if (item.IndexOf('/') > 0)
                {

                    //a = a.Replace(item, Convert.ToDateTime(item).ToString("dd/MM/yyyy"));
                    newItem = Regex.Replace(item, pattern, "$2/$1/$3", RegexOptions.None, TimeSpan.FromMilliseconds(150));

                    a = a.Replace(item, newItem);

                }


            }

            return a;

        }

 2. 判断一条语句是否是 palindrome (回文)

public static bool IsPalindrome(string s)

        {

            

            string newS = s.Replace(" ", "").ToLower();

            //Get the first and last index of the string

             int beginIndex = 0;

            int endIndex = newS.Length - 1;




            //Compare and judge whether the char is same from begin and end direction

            while (beginIndex < endIndex)

            {

                if (newS[beginIndex] != newS[endIndex])

                    return false;




                beginIndex++;

                endIndex--;

            }




            return true;

        }