DAY5：leetcode #7 Reverse Integer

最新推荐文章于 2022-09-30 15:07:28 发布

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本文介绍了一个简单的算法，用于反转一个32位整数，并考虑了输入整数末位为0及反转后可能产生的溢出情况。

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

click to show spoilers.

Have you thought about this?

Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!

If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100.

Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?

For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Update (2014-11-10):
Test cases had been added to test the overflow behavior.

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class Solution(object):
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        s = str(x)
        if '-' in s:
            r = '-' + s[1:][::-1]
        else:
            r = s[::-1]
        if int(r) > 2147483647 or int(r) < -2147483647:
            return 0
        else:
            return int(r)

最后的处理有点蠢，在python好像是不会出现整数溢出这种现象的，所以就索性判断了一下。