Description

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0.

Example 1:

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Input: x = 123
Output: 321

Example 2:

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Input: x = -123
Output: -321

Example 3:

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Input: x = 120
Output: 21

Example 4:

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Input: x = 0
Output: 0

Constraints:

  • -2^31 <= x <= 2^31 - 1

Approach

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class Solution:
    def reverse(self, x: int) -> int:
        sign = -1 if x < 0 else 1
        x = abs(x)

        reversed_x = 0
        while x > 0:
            reversed_x = reversed_x * 10 + x % 10
            x //= 10

        reversed_x *= sign

        if reversed_x < -2**31 or reversed_x > 2**31 - 1:
            return 0

        return reversed_x