如何在C#中检查anagram字符串

Question

给定两个字符串A和B,检查它们是否是字谜.

如果通过重新排列另一个字母可以获得一个字符串,则称两个字符串为字谜.

字谜的例子是

• dog, god
• abac, baac
• 123, 312

abab, aaba而dab, baad不是字谜.

输入:

输入的第一行是测试用例T的数量.接着是T行,每行有两个空格分隔的字符串A和B;

OUTPUT

对于每个测试用例,如果是anagrams则打印"YES",否则打印"NO".(不含引号)

约束

1. 1 <= T <= 10
2. A和B都只包含小写拉丁字母'a'到'z'和数字0到9.
3. 每根弦A和B的长度不超过5*10 ^ 5(500000)

`

Sample Input            Sample Output
------------------------------------
3                           YES
abcd bcda                   NO
bad daa                     YES
a1b2c3 abc123               NO

我们应该怎么做 ？

bool anagramChecker(string first, string second)
{
    if(first.Length != second.Length)
        return false;

    if(first == second)
        return true;//or false: Don't know whether a string counts as an anagram of itself

    Dictionary<char, int> pool = new Dictionary<char, int>();
    foreach(char element in first.ToCharArray()) //fill the dictionary with that available chars and count them up
    {
        if(pool.ContainsKey(element))
            pool[element]++;
        else
            pool.Add(element, 1);
    }
    foreach(char element in second.ToCharArray()) //take them out again
    {
        if(!pool.ContainsKey(element)) //if a char isn't there at all; we're out
            return false;
        if(--pool[element] == 0) //if a count is less than zero after decrement; we're out
            pool.Remove(element);
    }
    return pool.Count == 0;
}

Answer 1

这是你的解决方案吗？

string a = "abcd";
string b = "bcda"; // bad daa a1b2c3 abc123

string aa = String.Concat(a.OrderBy(c => c));
string bb = String.Concat(b.OrderBy(c => c));

if (aa == bb)
{
     Console.WriteLine("YES");
}
else
{
     Console.WriteLine("NO");
}

或更短

if (String.Concat(a.OrderBy(c => c)).Equals(String.Concat(b.OrderBy(c => c))) ...

Answer 2

有快速的方法和简单的方法：

void Test()
{
    string a = "abccabccabccabccabccabccabccabccabccabccabccabccabccabccabccabcc";
    string b = "bcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcacbcac";

    IsAnagramSimple(a, b);
    IsAnagramFast(a, b);
}


private bool IsAnagramSimple(string a, string b)
{
    return a.OrderBy(c => c).SequenceEqual(b.OrderBy(c => c));
}

private bool IsAnagramFast(string a, string b)
{
    if (a.Length != b.Length)
    {
        return false;
    }

    var aFrequency = CalculateFrequency(a);
    var bFrequency = CalculateFrequency(b);

    foreach (var key in aFrequency.Keys)
    {
        if (!bFrequency.ContainsKey(key)) return false;
        if (aFrequency[key] != bFrequency[key]) return false;
    }

    return true;
}

private Dictionary<char, int> CalculateFrequency(string input)
{
    var frequency = new Dictionary<char, int>();
    foreach (var c in input)
    {
        if (!frequency.ContainsKey(c))
        {
            frequency.Add(c, 0);
        }
        ++frequency[c];
    }
    return frequency;
}

Answer 3

public bool IsAnagram(string s1,string s2)
{
  if (s1.Length != s2.Length)
     return false;
  var s1Array = s1.ToLower().ToCharArray();
  var s2Array = s2.ToLower().ToCharArray();

  Array.Sort(s1Array);
  Array.Sort(s2Array);

  s1 = new string(s1Array);
  s2 = new string(s2Array);

  return s1 == s2;
}

Answer 4

class Anagrams
{
    static void Main()
    {
        // 1
        // Read and sort dictionary
        var d = Read();

        // 2
        // Read in user input and show anagrams
        string line;
        while ((line = Console.ReadLine()) != null)
        {
            Show(d, line);
        }
    }

    static Dictionary<string, string> Read()
    {
        var d = new Dictionary<string, string>();
        // Read each line
        using (StreamReader r = new StreamReader("enable1.txt"))
        {
            string line;
            while ((line = r.ReadLine()) != null)
            {
                // Alphabetize the line for the key
                // Then add to the value string
                string a = Alphabetize(line);
                string v;
                if (d.TryGetValue(a, out v))
                {
                    d[a] = v + "," + line;
                }
                else
                {
                    d.Add(a, line);
                }
            }
        }
        return d;
    }

    static string Alphabetize(string s)
    {
        // Convert to char array, then sort and return
        char[] a = s.ToCharArray();
        Array.Sort(a);
        return new string(a);
    }

    static void Show(Dictionary<string, string> d, string w)
    {
        // Write value for alphabetized word
        string v;
        if (d.TryGetValue(Alphabetize(w), out v))
        {
            Console.WriteLine(v);
        }
        else
        {
            Console.WriteLine("-");
        }
    }
}