LeetCode #9 – Palindrome Number

LeetCode题目链接

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.

题意:给定一个数字,判断是否为回文串。要求不能使用额外空间。

手动反转,判断与原数字是否相等即可。

class Solution:
    def isPalindrome(self, x):
        t, xx = 0, x
        while x > 0:
            t = t * 10 + x % 10
            x //= 10
        return t == xx

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