Calculate the number of bits. Then compare a pair of bits each time.

For example "12321", compare '1' with '1' then '2' with '2'.

```
class Solution {
public:
bool isPalindrome(int x) {
if (x<0) {
return false;
}
int numbit=0;
int n=x;
while (n>0) {
n /= 10;
numbit++;
}
for (int i=0; i<numbit/2; i++) {
int right = x/pow(10,i);
right %= 10;
int left = x/pow(10,numbit-i-1);
left %= 10;
if (right != left) {
return false;
}
}
return true;
}
};
```