第一周OJ-Q7解题方法

题目：Reverse digits of an integer.

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

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Note:
The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.

class Solution(object):
    def reverse(self, x):
        result = 0
        xx = 0
        if x<0:
            xx = (-1)*x
        else:
            xx = x
        while xx>0:
            result = result*10+xx%10
            xx = xx/10
        if result>=2147483648 or result<-2147483648:
            return 0
        if x<0:
            return (-1)*result
        if x>=0:
            return result

直接上源码，先判断数字符号，然后不停取出输入的最后一位并删除。在result中，把得到的每一位数字依次往前推，具体做法是乘以10并加上下一个取出的末位。通过的结果如下图。