The most obvious idea is to maintain two divisors to get the most and least significant digits and compare them. Well, there are much more clever ideas, like , whose code is rewritten below. Play with it :-)

1 class Solution { 2 public: 3     bool isPalindrome(int x) { 4         if (x < 0 || (x && !(x % 10))) return false; 5         int s = 0; 6         while (x > s) { 7             s = s * 10 + x % 10; 8             x /= 10; 9         }10         return x == s || x == s / 10;11     }12 };