message: Update reverse-bits.cpp
diff: -// Time: O(logn) = O(32)
  +// Time: O(32)
  // Space: O(1)
  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;
  + }
  +};
  +
  +// Time: O(logn) = O(32)
  +// Space: O(1)
  +class Solution2 {
  public:
  uint32_t reverseBits(uint32_t n) {
  uint32_t result = 0;
  