Determine whether an integer is a palindrome. Do this without extra space.
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.
// Palindrome Number.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <iostream>
using namespace std;
class Solution {
public:
bool isPalindrome(int x) {
if (x < 0)
return false;
int maxB = 1;
int tempX=x;
tempX = tempX / 10;
while (tempX != 0)
{
maxB = maxB * 10;
tempX = tempX / 10;
}
bool flag = true;
while (x)
{
int top = x / maxB;
int bottom = x % 10;
if (top != bottom)
{
flag = false;
break;
}
x = x - top*maxB;
x = x / 10;
maxB /= 100;
}
return flag;
}
};
int _tmain(int argc, _TCHAR* argv[])
{
Solution ss;
cout << ss.isPalindrome(515) << endl;
system("pause");
return 0;
}
原文：http://www.cnblogs.com/supernigel/p/4031910.html