Problem URL: Palindrome number

We can convert the number to string, reverse it and then check whether it's palindrome of not.

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

Time Complexity: O(n)
Space Complexity: O(n)

First of all it the number is negative or the last digit of the number is 0, then it can't be a palindrome. Then we start from the end digit, creating a new number from that. If the new number is equal to the original number, then we return true, else false.

class Solution:
    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 x == result or x == result//10

Time Complexity: O(n)
Space Complexity: O(1)