def _solve(self):
        t = self._text_matrix.copy()
        d = self._distance_matrix.copy()

        num_cols = d.shape[1]
        m = []
        for _ in range(num_cols):
            m.append([{'cost': 0, 'seq': []} for _ in range(num_cols)])
        for i in range(num_cols):
            m[0][i]['cost'] = 0
            m[0][i]['seq'] = [i]
        for i in range(num_cols - 1):
            for j in range(num_cols):
                for k in range(num_cols):
                    if k not in m[i][j]['seq']:
                        old = m[i + 1][k]['cost']
                        new = m[i][j]['cost'] + d[j][k]
                        if new > old:
                            m[i + 1][k]['cost'] = new
                            m[i + 1][k]['seq'] = m[i][j]['seq'] + [k]

        mx = 0
        for i in range(1, num_cols):
            if m[-1][i]['cost'] > m[-1][mx]['cost']:
                mx = i
        p = m[-1][mx]['seq']
        return t[:, p]