题目描述：

https://leetcode.com/problems/reverse-bits/
Code:

//solution one
class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
        n = (n >> 16) | (n << 16);
        n = ((n & 0xff00ff00) >> 8) | ((n & 0x00ff00ff) << 8);
        n = ((n & 0xf0f0f0f0) >> 4) | ((n & 0x0f0f0f0f) << 4);
        n = ((n & 0xcccccccc) >> 2) | ((n & 0x33333333) << 2);
        n = ((n & 0xaaaaaaaa) >> 1) | ((n & 0x55555555) << 1);
        return n;
    }
};

//solution two
class Solution {
public:
uint32_t reverseBits(uint32_t n) {
    uint32_t m = 0;
    for (int i = 0; i < 32; i++, n >>= 1) {
        m <<= 1;
        m |= n & 1;
    }
    return m;
}
};