2.[easy] Reverse Integer

Reverse digits of an integer.

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

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.

这里如果用纯数学上的解法，负数取余会存在问题。因此不如先转换成字符列表来处理，较为直观

class Solution(object):    def reverse(self, x):        """        :type x: int        :rtype: int        """        x_temp = list(str(x))        x_ge = True        if x < 0:            x_ge = False            x_temp = list(str(x))[1:]        x_temp = x_temp[::-1]        x_temp_copy = x_temp.copy()        for i in range(len(x_temp)):            if x_temp[i] == "0" and len(x_temp) != 1:  # 排除0这个数                x_temp_copy.pop(0)            else:                break        if x_ge:            return int("".join(x_temp_copy))        else:            return int("-" + "".join(x_temp_copy))