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.

如果是負數，則不是迴文數；如果是零，是迴文數，那大於零怎麼判斷呢？

我思考，如果我們可以把數正着寫和逆着寫的數字是一樣，那這個數就是迴文數。

下面見代碼。

class Solution {
public:
    bool isPalindrome(int x) {
        if(x < 0)
            return false;
        else if(x == 0)
            return true;
        else
        {
            int z = x;
            int y = 0;
            while(x != 0)
            {
                y = y*10 +x%10;
                x = x/10;
            }
            if(y == z)
                return true;
            else
                return false;
        }
    }
};