Palindrome Number （回文数）

回文数是指这样的数字：正读和倒读都是一样的。如：595，2332都是回文数，234不是回文数。

注意：负数不是回文数

 

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

 

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.

Solution:

bool isPalindrome(int x) {
      if(x<0) return false;
      vector<int>m;
      if(x<10)
           return true;
      while(x)
      {
           m.push_back(x%10);
           x/=10;
      }
      int l=0,r=m.size()-1;
      while(l<r)
     {
          if(m[l]!=m[r])
               return false;
          l++;
          r--;
     }
     return true;
}