9. Palindrome Number

Given an integer x, return true if x is a palindrome, and false otherwise.

Example 1:

Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.

Example 2:

Input: x = -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 2:

Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

Constraints:

• -231 <= x <= 2^31 - 1

Code

String

class Solution:
    def isPalindrome(self, x: int) -> bool:
        x = str(x)
        xr = x[::-1]

        return x == xr

Math

class Solution:
    def isPalindrome(self, x: int) -> bool:
        if x < 0:
            return False

        reversed_num = 0
        temp = x

        while temp != 0:
            digit = temp % 10
            reversed_num = reversed_num * 10 + digit
            temp //= 10

        return reversed_num == x