7.reverse-integer.python3.py

#
# [7] Reverse Integer
#
# https://leetcode.com/problems/reverse-integer/description/
#
# algorithms
# Easy (24.43%)
# Total Accepted:    480.9K
# Total Submissions: 2M
# Testcase Example:  '123'
#
# Given a 32-bit signed integer, reverse digits of an integer.
# 
# Example 1:
# 
# 
# Input: 123
# Output: 321
# 
# 
# Example 2:
# 
# 
# Input: -123
# Output: -321
# 
# 
# Example 3:
# 
# 
# Input: 120
# Output: 21
# 
# 
# Note:
# Assume we are dealing with an environment which could only store integers
# within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of
# this problem, assume that your function returns 0 when the reversed integer
# overflows.
# 
#
class Solution:
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        ans = str(x)[::-1] if x >= 0 else '-' + str(x)[:0:-1]
        ans = int(ans)
        if ans < - 2 ** 31 or ans > 2 ** 31 - 1:
            ans = 0

        return ans