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?

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;
}