different computation of curr_bound for level 2 from the other levels
if level == 1 : NEW_LINE INDENT curr_bound -= ( ( firstMin ( adj , curr_path [ level - 1 ] ) + firstMin ( adj , i ) ) / 2 ) NEW_LINE DEDENT else : NEW_LINE INDENT curr_bound -= ( ( secondMin ( adj , curr_path [ level - 1 ] ) + firstMin ( adj , i ) ) / 2 ) NEW_LINE DEDENT