Leetcode 9 Palindrome Number

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

click to show spoilers.

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.

不多说了，直接贴代码，注意特判负数不是回文数就行了

代码语言：javascript复制

class Solution {
public:
    bool isPalindrome(int x) 
    {
        if(x<0) return false;
        int base=1;
        while(x/base>=10)
            base*=10;
        while(x)
        {
            if(x/base!=x) return false;
            x=x-x/base*base;
            x/=10;
            base/=100;
        }
        return true;
    }
};

click handle integer palindrome space

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