```
class Solution(object):
def isStrobogrammatic(self, num):
"""
:type num: str
:rtype: bool
"""
hashmap = {6:9, 9:6, 1:1, 0:0, 8:8}
if len(num) < 1: return True
left = 0
right = len(num)-1
while(left <= right):
if int(num[left]) not in hashmap or int(num[right]) not in hashmap:
return False
if int(num[left]) != hashmap[int(num[right])]:
return False
left += 1
right -= 1
return True
```