shorter concat [reverse longer]

shorter concat [reverse longer]

Description:

Given 2 strings, a and b, return a string of the form: shorter+reverse(longer)+shorter.

In other words, the shortest string has to be put as prefix and as suffix of the reverse of the longest.

Strings a and b may be empty, but not null (In C# strings may also be null. Treat them as if they are empty.).
If a and b have the same length treat a as the longer producing b+reverse(a)+b

我的解法，让人不满意的是if和else的判断太多了。

空字符串和非空字符串，本身是可以直接拼接的

using System;
using System.Linq;

class ReverseLonger
{
  public static string ShorterReverseLonger(string a, string b)
  {
      a = a ?? string.Empty;
            b = b ?? string.Empty;
            string str = string.Empty;
            if (a.Equals(string.Empty))
            {
                if (b.Equals(string.Empty))
                { }
                else
                {
                    str = string.Join(string.Empty, b.Reverse());
                }
            }
            else
            {
                if (b.Equals(string.Empty))
                {
                    str = string.Join(string.Empty, a.Reverse());
                }
                else
                {
                    if (a.Length < b.Length)
                    {
                        str = a + string.Join(string.Empty, b.Reverse()) + a;
                    }
                    else
                    {
                        str = b + string.Join(string.Empty, a.Reverse()) + b;
                    }
                }
            }
            return str;
  }
}

其他人的解法：

比我好的地方是，通过比较大小，之后用统一的格式来处理

using System.Linq;

class ReverseLonger
{
  public static string ShorterReverseLonger(string a, string b)
  {
    if(a == null)
      a = string.Empty;
    if(b == null)
      b = string.Empty;

    if(a.Length < b.Length)
    {
      string d = a;
      a = b;
      b = d;
    }

    return b + (new string(a.Reverse().ToArray())) + b;
  }
}