leetcode

Leetcode - Palindrome Number Solution

Bodo Coder

— 1 min read

Given an integer x, return true if x is palindrome integer.

An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.

Example 1:

Input: x = 121
Output: true

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.

Example 4:

Input: x = -101
Output: false

Constraints:

  • -231 <= x <= 231 - 1

Follow up: Could you solve it without converting the integer to a string?

Solution in Python

class Solution:
    def isPalindrome(self, x: int) -> bool:
        number = x
        reverse_number = 0
        while number>0:
            remainder = number %10
            number = (number - remainder)//10
            reverse_number= reverse_number*10+remainder
        return x == reverse_number

Read more