7. Reverse Integer

Easy

Given a 32-bit signed integer, reverse digits of an integer. 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.

😇 Solution

O(n)

class Solution:
    def reverse(self, x: int) -> int:
        
        sign = 1
        if x < 0:
            sign = -1
        x = x*sign
        
        ans = 0
        while(x>0):
            q = x % 10
            ans = ans*10 + q
            x = int(x/10)
        
        res = sign*ans
        return 0 if (res >= 2**31-1 or res <= -2**31) else res