Reverse bits of a given 32 bits signed integer.
Example 1:
Input: n = 43261596
Output: 964176192
Explanation:
| Integer | Binary |
|---|---|
| 43261596 | 00000010100101000001111010011100 |
| 964176192 | 00111001011110000010100101000000 |
Example 2:
Input: n = 2147483644
Output: 1073741822
Explanation:
| Integer | Binary |
|---|---|
| 2147483644 | 01111111111111111111111111111100 |
| 1073741822 | 00111111111111111111111111111110 |
Constraints:
0 <= n <= 231 - 2n is even.
Follow up: If this function is called many times, how would you optimize it?