一c#面试题

Question

string a;
string b;
假如a="abcdefg"，b="bcde"
判断如果b属于a，则b倒序排列一下，然后替换b在a中的位置输出一段新的字符串例如 初始化a="abcdefg"，b="bcde"
通过调用一个方法输出a="aedcbfg"不能使用indexof()和replace()方法

Answer 1

只提供思路，把string看做是一个个char
依次比较然后替换
类似重写indexof和replasce方法

Answer 2

  既然不能使用indexof()和replace()方法，那就用数组做

Answer 3

不用太考虑性能的话string a = "abcdefg", b = "bcde";
if (a.Contains(b))
    a = a.Replace(b, new string(b.ToCharArray().Reverse().ToArray()));

Answer 4

        string MyReplace(string a, string b)
        {
            int index = -1;
            for (int i = 0; i < a.Length; i++)
            {
                if (a[i] == b[0])
                {
                    bool exsits = true;
                    for (int j = 1; j < b.Length; j++)
                    {
                        if (a[i + j] != b[j])
                            exsits = false;
                    }
                    if (exsits)
                    {
                        index = i;
                        break;
                    }
                }
            }
            if (index == -1)
                return a;
            char[] cs = new char[a.Length];
            for (int i = 0; i < a.Length; i++)
            {
                if (i >= index && i < index + b.Length)
                    cs[i] = b[b.Length - 1 - (i - index)];
                else
                    cs[i] = a[i];
            }
            return new string(cs);
        }

Answer 5

string StrReplace(string a, string b)
    {
        string returnValue = string.Empty;
        for (int i = 0; i < a.Length - b.Length; i++)
        {
            if (a.Substring(i, b.Length) == b)
            {
                char[] newArray = b.ToCharArray();
                Array.Reverse(newArray);
                returnValue = a.Remove(i, b.Length).Insert(i, new String(newArray));
            }
        }
        return returnValue;
    }

Answer 6

   string a="abcdefg";
        string b = "bcde";
        if (a.Contains(b))
        {
            int count = b.Length - 1;
            char[] chArr = new char[b.Length];
            for (int i = 0; i <= count; i++)
            {
                chArr[i] = b[count - i];
            }
            int index = a.IndexOf(b);
            string resultStr = a.Remove(index,b.Length).Insert(index, new string(chArr));
            Response.Write(resultStr);
        }

Answer 7

哪位大牛能用Regex给实现下？？？？？？？？？？？？？？？？？？？？？？？？？？？？

Answer 8

        static string MyReplace(string a, string b)
        {
            return Regex.Replace(a, b, match => { char[] cs = match.Value.ToCharArray(); Array.Reverse(cs); return new string(cs); });
        }

Answer 9

 static void Main(string[] args)
        {
            string a = "abcdefg";
            string b = "bcde";
            string[] s_a=a.Split(new string[] { b }, StringSplitOptions.RemoveEmptyEntries);
            if (s_a.Length > 0)
            {
                char[] c_b = b.ToCharArray().Reverse().ToArray();
                string temp = new String(c_b);
                StringBuilder sBuild=new StringBuilder();
                for (int i = 0; i < s_a.Length - 1; i++)
                {
                    sBuild.AppendFormat("{0}{1}",s_a[i],temp);
                }
                sBuild.Append(s_a[s_a.Length-1]);
                a = sBuild.ToString();
            }
            
            Console.WriteLine(a);
        }

Answer 10

 string a="abcdefg";
        string b = "bcde";       
        if (a.Contains(b))
        {
            int count = b.Length - 1;
            char[] chArr = new char[b.Length];
            for (int i = 0; i <= count; i++)
            {
                chArr[i] = b[count - i];
            }            string str = new string(chArr);            int index = 0;
            for (int i = 0; i < a.Length; i++)
            {
                if (a[i] == b[0])
                { 
                  index = i;
                }
            }           
            string resultStr = a.Remove(index,b.Length).Insert(index, new string(chArr));
            Response.Write(resultStr);

Answer 11

   string a = "abcdefg";
            string b="bcde";
            var dest=a.ToCharArray().Intersect(b.ToCharArray()).Reverse();//取出重复的值并且反转
            char[] c=b.ToCharArray();
            string[] arrstr=a.Split(c);
             string news=arrstr[0]+new string(dest.ToArray()) + arrstr[arrstr.Length-1];
             Console.WriteLine(news);

Answer 12

 private string changeStr(string longer,string shorter)
        {            
            if (longer.Contains(shorter))
            {
                char[] l = longer.ToCharArray();
                char[] s = shorter.ToCharArray();
                char[] sr = new char[s.Length];
                int startindex = -1;
                for (int i = 0; i < l.Length; i++)//长字符串
                {
                    for (int j = 0; j < s.Length; j++)//短字符串
                    {
                        if (l[i] == s[j])//有一位相同，检查余下位数是否相同
                        {
                            startindex = i;
                            int tmp = i+1;
                            sr[0] = s[s.Length-1];
                            for (int k = 1; k < s.Length; k++)
                            {
                                sr[k] = s[s.Length - 1 - k];
                                if (l[tmp] != s[k])//非全部相同将继续循环
                                {
                                    startindex = -1;
                                    sr = new char[s.Length];                                    
                                    break;
                                }
                                tmp++;
                            }                            
                        }
                        break;
                    }
                    if (startindex != -1)
                        break;
                }                for (int i = 0; i < s.Length; i++)
                {
                    l[startindex + i] = sr[i];
                }
                return new string(l);
            }
            return null;
        }
不够精简……

Answer 13

        static void Main(string[] args)
        {
            string original1 = "abcdefg";
            string original2 = "bcd";
            char[] chr2Reverse = original2.ToCharArray();
            Array.Reverse(chr2Reverse);
            string reverseStr = new String(chr2Reverse);
            if (original1.Contains(original2))
            {
                string[] original1Split = original1.Split(original2.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                System.Text.StringBuilder sb = new System.Text.StringBuilder();
                for (int i = 0; i < original1Split.Length; i++)
                {
                    sb.Append(original1Split[i]);
                    if (i + 1 < original1Split.Length)
                    {
                        sb.Append(reverseStr);
                    }
                }               
                Console.WriteLine(sb.ToString());
            }            Console.ReadLine();
         }

Answer 14

看到很多的算法似乎只替换了一次。
如果初始化a = "abbaab",b = "ab";
调用方法后是不是输出这样的结果：a = "bbbaaa";

Answer 15

按LZ的意思，正确的结果应该是bababa

Answer 16

  string inputb="def"; //输入B
            string inputa = "abcdef";//输入A
            string outputb = string.Empty;//输出
            if (inputa.Contains(inputb))
            {                string[] strarry = inputa.Split(inputb.ToCharArray(),  System.StringSplitOptions.RemoveEmptyEntries);
                for (int i = inputb.Length - 1; i >= 0; i--)
                {
                    outputb += inputb.Substring(i, 1);
                }
           
                //textBox_OUTPUT.Text = textBox_A.Text.Replace(inputb, outputb);
                if (strarry.Length > 1)//B在A中间
                {
                    outputb = strarry[0] + outputb + strarry[1];
                }
                else if (strarry.Length ==1)//B包含A开头或结尾
                {
                    outputb = strarry[0] + outputb;
                }
                //B=A,直接输出outputb
            }
        }

Answer 17

只是“不能使用indexof()和replace()方法”嘛...C#嘛，你们搞那么复杂干什么...一句的事儿...
return string.Join(new string(b.Reverse().ToArray()),a.Split(new string[]{b}))

Answer 18

Split()的参数是不是只能字符啊。。