Consider the numbers 6969 and 9116. When you rotate them 180 degrees (upside down), these numbers remain the same. To clarify, if we write them down on a paper and turn the paper upside down, the numbers will be the same. Try it and see! Some numbers such as 2 or 5 don't yield numbers when rotated.
Given a range, return the count of upside down numbers within that range. For example, solve(0,10) = 3, because there are only 3 upside down numbers >= 0 and < 10. They are 0, 1, 8.
More examples in the test cases.
Good luck!
def solve(a, b):
passdef solve(a, b):
nums = {"0": "0", "1": "1", "6": "9", "8": "8", "9":"6"}
tot = 0
for i in range(a,b):
i = str(i)
m = "".join([nums[x] for x in i[::-1] if x in nums])
if i == m:
tot +=1
return tot