Pseudocode:
map['0'] = '0';
map['1'] = '1';
map['2'] = '2';
map['5'] = '5';
map['6'] = '9';
map['8'] = '8';
map['9'] = '6';
for each position i in input_string :
if map index exists for input_string[i] :
rotated_string[i] = map[input_string[i]]
else
exit for
rotated_string = reverse(rotated_string)
if input_string = rotated_string :
has_rotational_symmetry = true
else
has_rotational_symmetry = false