算法高手请进

#pragma warning(disable : 4786)

#include <iostream>

#include <string>

#include <deque>



#define BUFFSIZE 1024



using std::cout;

using std::endl;

using std::string;

using std::deque;



typedef deque<string> strlist;



const string::size_type npos = -1;

const string ignoreChars(" \t\n\r");



inline bool IgnoreChar(char c){

    return (ignoreChars.find(c) != npos);

}



/*

 * 统计字符出现次数

 */

unsigned CharSummary(const string& text, unsigned usecount[], int tbllen){

    unsigned count, i;



    memset(usecount, 0, tbllen * sizeof(unsigned));

    for(i = 0;i < text.length();usecount[unsigned(text[i++])]++);



    for(count = i = 0;i < 256;i++){

        if(IgnoreChar(i))continue;

        if(usecount[i] > count)count = usecount[i];

    }



    return count;

}



/*

 * 试着增长字符串

 */

char TryGrowthString(const string& text, const string& str, int maxcount, unsigned* usecount){

    int count;

    string::size_type pos;

    char c = 0;



    pos = text.find(str);

    if(pos == npos)

        return 0;



/*  不是出现次数最多的字符 */

    c = text[pos + str.length()];

    if(usecount[unsigned(c)] < maxcount)

        return 0;



/*  检查文本中的出现次数 */

    for(count = 0; pos + str.length() + 1 < text.length();pos += str.length()){

        pos = text.find(str, pos);

        if(pos == npos) break;

        if(c != text[pos + str.length()]) return 0;

    }



    return c;

}



void PrintResult(const strlist& result){

    strlist::const_iterator citer;



    cout<<endl<<"The result substrings :"<<endl;

    cout<<"-------------------------------------"<<endl;

    for(citer = result.begin(); citer != result.end(); citer++){

        cout<<'"'<<*citer<<'"'<<endl;

    }

    cout<<"-------------------------------------"<<endl;

    cout<<"Total : "<<result.size()<<endl;

}



void main(void){

    unsigned usecount[256];

    char buffer[BUFFSIZE], c;

    unsigned count, i;

    string text;

    strlist result;



/*

 * 从 stdin 读入文本

 */

    while(!feof(stdin)){

        if(fgets(buffer,sizeof(buffer),stdin))

            text += buffer;

    }



/*

 * 统计字符出现次数

 */

    count = CharSummary(text, usecount, sizeof(usecount) / sizeof(*usecount));

    cout<<"Max count :"<<count<<endl;



    if(0 == count){

        cout<<"There is empty string!"<<endl

            <<"Bye!"<<endl;

    }



/*

 * 将出现次数最多的字符作为子串放入结果中

 */

    for(i = 0;i < sizeof(usecount) / sizeof(*usecount);i++){

        if(usecount[i] == count)

            result.push_back(string(1,char(i)));

    }



/*

 * 查找更多的子串

 */

    for(strlist::iterator iter = result.begin();iter != result.end();iter++){

        c = TryGrowthString(text, *iter, count, usecount);

        if(c)

            result.push_back(*iter + string(1, c));

    }



    PrintResult(result);

    cout<<"Bye!"<<endl;

}