Description

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

Example 1:

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

Example 2:
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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 3:
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Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

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Constraints:

-231 <= x <= 231 - 1

Approach

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class Solution:
    def isPalindrome(self, x: int) -> bool:
        if x < 0 or (x != 0 and x % 10 == 0):
            return False
        
        half = 0

        while x > half:
            half = x % 10 + half * 10 
            x //= 10

        return half == x or x == half // 10