Reverse bits of a given 32 bits unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as 00111001011110000010100101000000).

Follow up:

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

Related problem: Reverse Integer

class Solution {public:    uint32_t reverseBits(uint32_t n) {        uint32_t num = 0;        for(int i=0;i<32;++i)        {            num = (num<<1)+(n>>i&1);        }        return num;    }};