7. Reverse Integer【E】【27】-优快云博客

本文介绍了一种用于反转整数的算法实现，包括处理负数、去除前导零及检查32位整数溢出等特殊情况。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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.

Subscribe to see which companies asked this question

需要考虑的情况还不少

class Solution(object):
    def reverse(self, x):
        minus = False
        s = list(str(x))
        if s[0] == '-':
            s = s[1:]
            minus = True
        s.reverse()
        
        if minus:#负数的情况
            res = '-'
        else:
            res = ''
        
        while len(s) > 0 and s[0] == '0': #首位为0的
            del s[0]
        for i in s:
            res += i
        if res == '':
            res = 0
            
        res = int(res)
        maxx = 1 << 31
        #print maxx
        if res > maxx or res < -maxx:#正负数溢出的情况
            return 0
        return res
        """
        :type x: int
        :rtype: int
        """