9.Palindrome Number (INT)

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

 

class Solution {

public:

    bool isPalindrome(int x) {

        if(x < 0) return false; //别忘了负数的情况

        if(x == 0) return true;

        

        int tmp = x/10;

        int pHead = 1;

        int leftDigit, rightDigit, base;

        while(tmp){

            pHead*=10;

            tmp /= 10;

        }

          

        while(pHead >= 1){

            leftDigit = x/pHead;

            rightDigit = x%10;

            if(leftDigit != rightDigit) return false;

            x %= pHead;

            x /= 10;

            pHead /= 100;

        }

        return true;

    }

};