Palindrome Number

Determine whether an integer is a palindrome. Do this without extra space.

方法：数字前后位分别提取并进行判断是否相等。

class Solution {
public:
    bool isPalindrome(int x) {
        if(x<0)
            return false;
        int y = x;
        int len = 1;
        while(y/10!=0){
            len++;
            y/=10;
        }
        bool isValid ;
        int left = len-1 ,right = 1;
        while(left >= right){
            int big = x /static_cast<int>(pow(10,left)) % 10;
            int small = x % static_cast<int>((pow(10,right)))/pow(10,right-1);
            if(big != small)
                return false;
            --left;
            ++right;
        }

        return true;
    }
};