[LeetCode] 9.Palindrome Number

原题：

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.

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解析：

先求出总共位数，然后首尾对应位相应比较

代码：

public class Solution { public boolean isPalindrome(int x) { int count=0; int n=x; int x1=x; int x2=x; int a,b; if(x<0 return="" false="" for="" int="" i="0;n">0;i++) { count++; n/=10; } for(int j=count;j>count/2;j--) { a=(int) (x1 / Math.pow(10, j - 1)); b=x2%10; if(a==b) { x1=(int) (x1 % Math.pow(10, j - 1)); x2=x2/10; } else return false; } return true; }}</0>