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).

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