9. Palindrome Number

class Solution {
public:
    bool isPalindrome(int x)
    {
        if (x < 0) return false;
        if (x != 0 && x % 10 == 0) return false;
        int reverted = 0;
        while (x > reverted)
        {
            int digit =  x % 10;
            x /= 10;
            reverted = reverted * 10 + digit;
        }
        return x == reverted || x == reverted / 10;
    }
};
  • T: O(N)O(N)
  • S: O(1)O(1)