LeetCode [7] Reverse Integer

Questions¶

Difficulty: Easy

Reverse digits of an integer.

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

Hint:

• 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.

Coding¶

python¶

# -*- coding: utf-8 -*-
class Solution(object):
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        n = None
        if x < 0:
            n = -x
        else:
            n = x
        s = str(n)
        s = s[::-1]
        if x < 0:
            n = -int(s)
        else:
            n = int(s)

        if n >= 2147483647 or n <= -2147483647-1:
            return 0
        return n