#include <string>
using std::string;

class LongestPalindromicSubstringSolution {
public:
    string longestPalindrome(string s) {

        if (s.length() == 1)
            return s;
        if (s.length() == 2) {
            if (s[0] == s[1])
                return s;

            char str[2];
            str[0] = s[0];
            str[1] = 0;
            return str;
        }

        const char* ptrStart = s.c_str();
        const unsigned long strLen = s.length();
        unsigned long strLongest = strLen;
        char *res = new char[strLen+1];
        memset(res, 0, strLen+1);

        for (; strLongest >= 2; strLongest--) {
            for (unsigned long i = 0; (i + strLongest) <= strLen; i++) {
                const char* start(ptrStart + i);
                const char* finish(start + strLongest - 1);

                while (start <= finish) {
                    if (*start != *finish) break;
                    start++;
                    finish--;
                }

                if (start > finish) {
                    memcpy(res, ptrStart + i, strLongest);
                    break;
                }
            }
            if (res[0] != 0) break;
        }

        if (res[0] == 0) {
            res[0] = s[0];
        }

        string resStr(res);
        delete [] res;

        return resStr;
    }
};