Leetcode: Reverse Bits

Reverse bits of a given 32 bits unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000).

Follow up:
If this function is called many times, how would you optimize it?

Related problem: Reverse Integer

Understand the problem:
We could get the least significant bit each time and append to the new result. 
e.g. 11100, we get 0 0 1 1 1, and append to the new result from right to left as well.

Code (Java):

public class Solution {
    // you need treat n as an unsigned value
    public int reverseBits(int n) {
        
        int result = 0;
        for (int i = 0; i < 32; i++) {
            result = (result << 1) | (n & 1);
            n = (n >> 1);
        }
        
        return result;
    }
}