Writing a string in a spiral

Question

I had recently participated in coding competion sponsored by an company and there was this one question which I did not understood, as to what was it asking.

Here i

Answer 1

//in c++

string convert(const string & s) { int len = s.size();

    //base case
    if (len == 0) return string("");

    // minimum square calculation
    int i = 1;
    while (i*i < len) ++i;
    //cout << "i=" << i << endl;

    //matrix initialization
    vector > matrix;
    matrix.resize(i);
    for (int j = 0; j < i; ++j)
            matrix[j].resize(i);
    for (int j = 0; j < i; ++j)
            for (int k = 0; k < i; ++k)
                    matrix[j][k] = ' ';

    //logic
    int r = 0, c = 0;
    bool right = true, down = false, left = false, up = false;      
    int curr_len = 0;
    int side = i - 1;
    while (curr_len < len)
    {
            if (right)
            {
                    for (int j = 1; (j <= side) && ((curr_len+j) <= len); ++j)
                    {
                            matrix[r][c] = s[curr_len];
                            //cout << curr_len << "|" << r << "|" << c << "|" << matrix[r][c] << "\n";
                            ++c;
                            ++curr_len;
                    }

                    right = false;
                    down = true;
            }

            if (down)
            {
                    for (int j = 1; (j <= side) && ((curr_len+j) <= len); ++j)
                    {
                            matrix[r][c] = s[curr_len];
                            //cout << curr_len << "|" << r << "|" << c << "|" << matrix[r][c] << "\n";
                            ++r;
                            ++curr_len;
                    }

                    down = false;
                    left = true;
            }

            if (left)
            {
                    for (int j = 1; (j <= side) && ((curr_len+j) <= len); ++j)
                    {
                            matrix[r][c] = s[curr_len];
                            //cout << curr_len << "|" << r << "|" << c << "|" << matrix[r][c] << "\n";
                            --c;
                            ++curr_len;
                    }

                    left = false;
                    up = true;
            }

            if (up)
            {
                    for (int j = 1; (j <= side) && ((curr_len+j) <= len); ++j)
                    {
                            matrix[r][c] = s[curr_len];
                            //cout << curr_len << "|" << r << "|" << c << "|" << matrix[r][c] << "\n";
                            --r;
                            ++curr_len;
                    }

                    up = false;
                    right = true;
                    side = side - 2;
                    ++r; ++c;
            }
    }

    stringstream ss;

    for (int j = 0; j < i; ++j)
    {
            for (int k = 0; k < i; ++k)
            {
                    ss << matrix[j][k];
            }
    }

    return ss.str();

}