LEETCODE 190

Reverse bits of a given 32 bits unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000).

思路：

本来求二进制的方法需要将得到的二进制代码从后往前排序，相当于这里需要的倒序，每求一位二进制，相当于除以二，倒序相当于乘以二。

当一个二进制位1010101111时，倒序为1111010101，这里要求32位，在后面添加0，相当于乘以2.

class Solution {public:    uint32_t reverseBits(uint32_t n) {        uint32_t sum = 0;        int count = 0;        while(n)        {            sum = sum * 2 + n%2;            n = n/2;            ++count;        }        for(int i = count; i < 32; ++i)            sum = sum *2;        return sum;    }};