###### tags: `Math` # LeetCode 9.Palindrome Number Given an integer ```x```, return ```true``` if ```x``` is a palindrome, and ```false``` otherwise. >Example 1: ``` IInput: 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 3: ``` Input: x = 10 Output: false Explanation: Reads 01 from right to left. Therefore it is not a palindrome. ``` ### Constraints: - $-2^{31} <= x <= 2^{31} - 1$ --- ### Idea: > ### Solution: Python: ```python= class Solution: import math def isPalindrome(self, x: int) -> bool: if x < 0 or (x > 0 and x%10 == 0): return False result = 0 while x > result: result = result * 10 + x % 10 x = x // 10 return True if (x == result or x == result // 10) else False ``` C++ ```cpp= ```