E190.颠倒二进制位

bit manipulation, https://leetcode.cn/problems/reverse-bits/

class Solution {
public:
    int reverseBits(int n) {
        unsigned int ori = n, ans = 0;
        for (int i = 0; i < 32; i++) {
            ans = (ans << 1) | (ori & 1);
            ori >>= 1;
        }
        return static_cast<int>(ans);
    }
};