Question 7: Reverse Integer
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 [-231, 231 - 1], then return 0.
Input: x = 123
Output: 321
Input: x = -123
Output: -321
Input: x = 120 Output: 21
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$-2^31$ <= x <=$2^31$ -1