C# と VB.NET の質問掲示板

C#で作ってみました
注)gcはガベージコレクションと無関係です orz

private GetCount CountValue(string target)
{
     IList<String> list = new List<String>();
     GetCount gc = null;
     // 文字を配列に格納
     for (int i = 0; i < target.Length; i++)
     {
            string tempValue = target.Substring(i, 1);
            list.Add(tempValue);
     }
     int baseCount = 0;
     // カウント
     foreach (string temp in list)
     {
            int searchCount = 0;
            if (baseCount == 0)
            {
                 foreach (string temp2 in list)
                 {
                    if (temp.Equals(temp2))
                    {
                       searchCount++;
                    }
                 }
                 if (baseCount < searchCount)
                 {
                 　　gc = new GetCount(searchCount, temp);
                     baseCount = searchCount;
                  }
            }
            else if (!temp.Equals(gc.KeyValue))
            {
                 foreach (string temp2 in list)
                 {
                     if (temp.Equals(temp2))
                     {
                         searchCount++;
                     }
                 }
                 if (baseCount < searchCount)
                 {
                       
                     gc = new GetCount(searchCount, temp);
                     baseCount = searchCount;
                 }
            }
       }
       return gc;
}

    public class GetCount
    {
        private int count = 0;
        private string keyValue = "";
        public GetCount(int _count, string _keyValue)
        {
            count = _count;
            keyValue = _keyValue;
        }
        public int Count
        {
            get { return count; }
            set { count = value; }
        }
        public string KeyValue
        {
            get { return keyValue; }
            set { keyValue = value; }
        }
    }

Dictionaryジェネリッククラスを使って作ってみました(C#)

private int CountValue(string target)
{
	Dictionary<char, int> dic = new Dictionary<char, int>();

	foreach (char c in target.ToCharArray()) {
		if (dic.ContainsKey(c))
			dic[c]++;
		else
			dic[c] = 1;
	}
	int max = 0;
	foreach (int n in dic.Values) {
		if (n > max)
			max = n;
	}
	return max;
}

#かぶった

C# の別解。

using System;
using System.Linq;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            string text = "asajd;alsfjsdlnrfguhdrlkhdltntnhldk;zdkfoajgriouheoutyeuoartahogruaerg";

            char c;
            int count = Program.Count(text, out c);

            Console.Out.WriteLine("{0} : {1}", c, count);
        }

        static int Count(string source, out char c)
        {
            int count = -1;
            c = '\0';

            var result = source.GroupBy(_ => _).Select(_ => new { Char = _.Key, Count = _.Count() }).OrderByDescending(_ => _.Count).FirstOrDefault();

            if (result != null)
            {
                c = result.Char;
                count = result.Count;
            }

            return count;
        }
    }
}

ま、まけるもんかあっ(C++)

#include <string>
#include <map>
#include <algorithm>

using namespace std;

int count(const string& in) {
  int result = 0;
  map<char,int> m;
  for_each(in.begin(),in.end(),[&](char c) { result = max(result, ++m[c]); });
  return result;
}

// おためし
#include <iostream>

int main() {
  cout << count("abca") << endl
       << count("aaaa") << endl
       << count("abbb") << endl
       << count("") << endl;
}

ついでにVB.NET LINQ 
※渋木宏明さんのとほぼ同じ

        Dim strSrc = "abcdfhhhujuaagbdcgekjfaufheufuanebvyewiendnedufdjhbcue"

        Dim itm = (From c In strSrc Group By c Into Cnt = Count() Order By Cnt Descending).FirstOrDefault

        If itm IsNot Nothing Then
            Console.WriteLine("{0}:{1}", itm.c, itm.Cnt)
        End If

Javaでもやってみた。

import java.util.*;

public class foo {

  public static int count(String input) {
    int result = 0;
    Dictionary<Character,Integer> dic = new Hashtable<Character,Integer>();
    for ( char ch : input.toCharArray() ) {
      Integer val = dic.get(ch);
      dic.put(ch, (val == null) ? 1 : val.intValue()+1);
      result = ( result < newValue ) ? newValue : result;
    }
    return result;
  }

  public static void main(String args[]) {
    System.out.println( count("abca") );
    System.out.println( count("aaaa") );
    System.out.println( count("abbb") );
    System.out.println( count("abcd") );
  }
}