190. Reverse Bits

题目：

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?

思路：

通过按位左移即可

代码：

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