Practice Reverse Integer

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#7

LeetCode Problem

Reverse Integer

Math

Problem Statement

Reverse the decimal digits of signed 32-bit integer x while retaining its sign. Return zero if the reversed value would fall outside [-2^31, 2^31 - 1]. The exercise does not permit a 64-bit integer to hold an intermediate result. Approach: Take one digit at a time from x and append it to the result. Before multiplying the result by ten or adding the digit, compare against the applicable 32-bit boundary. Checking only after arithmetic is too late in languages where that operation overflows. Removing trailing zeroes follows naturally from integer arithmetic.

Source: Reverse Integer on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input

x = -420

Output

-24

Explanation

Reverse the magnitude, discard the leading zero, and retain the negative sign.

# Example 2

Input

x = 1534236469

Output

Explanation

The reversed value would be 9646324351, beyond 2^31 - 1.

Constraints

-2^31 <= x <= 2^31 - 1

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