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.
Assume the environment does not allow you to store 64-bit integers (signed or unsigned).
Example 1:
Input: x = 123
Output: 321
Example 2:
Input: x = -123
Output: -321
Example 3:
Input: x = 120
Output: 21
Constraints:
$-2^{31} <= x <= 2^{31} - 1$給定一個 32-bit 的有號整數 num
要求寫一個演算法來反轉以10為base 的digit
如果是 32-bit 的有號整數
代表第一個位數是是 sign bit 用來表示症負號
代表最小數值是 -$2^{31}$ = 0b1000,0000,0000,0000,0000,0000,0000,0000