leetcode.9---------------Palindrome Number

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.

方法一：把整个数翻转过来  例如：1234变成4321   更多方法请参考https://oj.leetcode.com/discuss/oj/palindrome-number

class Solution {
public:
	bool isPalindrome(int x)
	{
		int m = x, n = 0;
		if (x < 0) return false;
		while (x) {
			n = n * 10 + x % 10;
			x = x / 10;
		}
		return (m == n);
	}
};

class Solution {
public:
	bool isPalindrome(int x) {
		// Start typing your C/C++ solution below
		// DO NOT write int main() function
		if (x < 0)
			return false;
		if (x == 0)
			return true;

		int base = 1;
		while (x / base >= 10)
			base *= 10;

		while (x)
		{
			int leftDigit = x / base;
			int rightDigit = x % 10;
			if (leftDigit != rightDigit)
				return false;
			x = x % base / 10;
			base /= 100;
		}

		return true;
	}
};