【leetcode】Reverse Bits

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?

 

class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
           uint32_t bit[32]={0};
           uint32_t ret=0;

           int mid=1;

           for(int i=0;i<32;i++)
           {
               bit[i]=(n>>i)&1;
           }

           for(int j=31;j>=0;j--)
           {
               ret=ret+bit[j]*mid;
               mid=mid*2;
           }

           return ret;

    }
};