Reverse All Bits of an Even Signed Integer
Company: Bloomberg
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Reverse the order of all 32 bits in the given signed-integer input and return the signed integer representing that reversed pattern. Leading zero bits participate; this is not reversal of only the significant digits.
```cpp
int reverseBits(int n);
```
### Examples
```text
Input: n = 2
Output: 1073741824
```
The bit at position 1 moves to position 30.
```text
Input: n = 12
Output: 805306368
```
### Constraints
- `0 <= n <= 2147483646`.
- n is even.
- Reverse exactly 32 bits; retain the signed int API.
### Optional follow-up
How would you optimize repeated calls to this function?
Overview: Reverse exactly 32 bits for the source’s even nonnegative signed-int domain, with safe internal shifts and repeated-call optimization.