Leetcode6: Palindrome Number

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

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Some hints:

Could negative integers be palindromes? (ie, -1)

If you are thinking of converting the integer to string, note the restriction of using extra space.

You could also try reversing an integer. However, if you have solved the problem "Reverse Integer", you know that the reversed integer might overflow. How would you handle such case?

There is a more generic way of solving this problem.

这道题的意思是判断一个数是否是回文数，即，如果是121那么这个数就是回文数。可以借鉴上一道题Leetcode5的思路来解决。

class Solution {
public:
    bool isPalindrome(int x) {
        int reverseX = reverseInteger(x);
        if(x == reverseX)
            return true;
        else
            return false;
    }
    int reverseInteger(int x)
    {
        long temp = 0;
        int sign = x > 0 ? 1 : -1;
        while(x)
        {
            temp = temp * 10 + x % 10;
            x /= 10;
        }
        if(temp > 2147483647 || sign*temp > 2147483647)
        {
            return 0;
        }
        else
            return temp*sign;
    }
};