Time complexity for a “Palindrome Number” solution

Question

This is a solution for solving LeetCode problem #9 Palindrome Number. I'm thinking about the time complexity of the solution. I try to understand the time complexity with examples.

Say for a 3-digit number, it goes through the while loop twice.

For a 6-digit number, it goes through the while loop 3 times.

I conclude the number increases 1000 times, while loop increases by 1.

So what's the time complexity?

Could anyone please explain to me? Thank you so much.

def isPalindrome(self, x):
    if x < 0 or (x > 0 and x % 10 == 0): return False
    half = 0
    while x > half:
        half, x = half * 10 + x % 10, x / 10
    return x in (half, half / 10)

Answer 1

x in (half, half/10) returns True if x is one of the two values in the tuple. It's equivalent to

x == half or x == half/10