#include <iostream>
#include <string>
#include <sstream>

using namespace std;

string getSubstring(string &s, int first, int last)     //возвращает подстроку от first до last включительно
{
    if (first <= last)
    {
        string substring = "";
        for (int i = first; i <= last; i++)
            substring += s[i];
        return substring;
    }
}

int stringLength(string &s)     //возвращает длину строки
{
    int i = 0;
    while (s[i])
        i++;
    return i;
}

bool isSubstring(string &str, string &substr, int substrBeginning)
{
    for (int i = 0; i < stringLength(substr); i++)
        if (str[substrBeginning + i] != substr[i])
            return false;
    return true;
}

bool substringsFirstCondition(string &str, string &substr, int center)      //проверяет, входит ли подстрока в строку только равноудаленно от концов
{
    int substringsCount = 1;
    for (int j = 0; j < stringLength(str) - stringLength(substr) + 1; j++)
        if (center != j)
            if (str[j] == substr[0])
                if (isSubstring(str, substr, j))
                {
                    if (j < center)
                    {
                        if (j != stringLength(str) - center - stringLength(substr))
                            return false;
                    }
                    else
                        if (center != stringLength(str) - j - stringLength(substr))
                            return false;
                substringsCount++;
                }
            if (substringsCount == 2)
                return true;
            else
                if (stringLength(str) - center - stringLength(substr) == center)
                    return true;
}

int substringsCount(string &str, string &substr, int center)        //возвращает количество вхождений подстроки в строку
{
    int counter = 1;
    for (int j = 0; j < str.length() - substr.length() + 1; j++)
        if (center != j)
            if (str[j] == substr[0])
            {
                if (isSubstring(str, substr, j))
                    counter++;
                if (counter > 2)
                    break;
            }
    return counter;
}

void processStrings(string &string1, string &string2, string &firstSubString, string &secondSubString, int first)
{
    for (int j = 0; j < stringLength(string1); j++)
    if (first <= j)
    {
        string check = getSubstring(string1, first, j);
        if (substringsFirstCondition(string1, check, first))
        {
            firstSubString = check;
            for (int k = 0; k < stringLength(string2) - stringLength(firstSubString) + 1; k++)
            {
                check = getSubstring(string2, k, k + stringLength(firstSubString) - 1);
                if (substringsCount(string2, check, k) <= 2)
                {
                    secondSubString = check;
                    break;
                }
            }
            if (secondSubString[0])
                break;
        }
    }
}

void findSubstrings(string &string1, string &string2, string &firstSubString, string &secondSubString)
{
    for (int i = 0; i < stringLength(string1); i++)
    {
        processStrings(string1, string2, firstSubString, secondSubString, i);
        if (secondSubString[0])
            break;
    }
}

string formResult(string &firstSubString, string &secondSubString)
{
    string result;
    if (secondSubString[0])
    {
        stringstream resultStream;
        for (int i = 0; i < stringLength(firstSubString); i++)
            resultStream << firstSubString[i] << secondSubString[i];
        result = resultStream.str();
    }
    else
        result = "There are no requiered substrings";
    return result;
}

int main()
{
    string string1, string2;
    cout << "Enter the first string: ";
    cin >> string1;
    cout << "Enter the second string: ";
    cin >> string2;
    string firstSubString, secondSubString;
    findSubstrings(string1, string2, firstSubString, secondSubString);
    cout << firstSubString << endl;
    cout << secondSubString << endl;
    string result = formResult(firstSubString, secondSubString);
    cout << result << endl;
    system("pause");
    return 0;
}