"""

Strobogrammatic Number Check

Determine whether a number (as a string) is strobogrammatic, meaning it

looks the same when rotated 180 degrees.

Reference: https://en.wikipedia.org/wiki/Strobogrammatic_number

Complexity:

Time: O(n) where n is the length of the number string

Space: O(1) for is_strobogrammatic, O(n) for is_strobogrammatic2

"""

from __future__ import annotations

def is_strobogrammatic(num: str) -> bool:

"""Check if a number string is strobogrammatic using two pointers.

Args:

num: String representation of the number.

Returns:

True if num is strobogrammatic, False otherwise.

Examples:

>>> is_strobogrammatic("69")

True

>>> is_strobogrammatic("14")

False

"""

comb = "00 11 88 69 96"

i = 0

j = len(num) - 1

while i <= j:

if comb.find(num[i] + num[j]) == -1:

return False

i += 1

j -= 1

return True

def is_strobogrammatic2(num: str) -> bool:

"""Check if a number string is strobogrammatic using string reversal.

Args:

num: String representation of the number.

Returns:

True if num is strobogrammatic, False otherwise.

Examples:

>>> is_strobogrammatic2("69")

True

>>> is_strobogrammatic2("14")

False

"""

return num == num[::-1].replace("6", "#").replace("9", "6").replace("#", "9")