LeetCode: 190. Reverse Bits

题目描述

Reverse bits of a given 32 bits unsigned integer.

Example:

Input: 43261596
Output: 964176192
Explanation: 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?

解题思路

重新申请一个无符号整数，然后将当前数字按位反向填入新申请的变量。

AC 代码

class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
        uint32_t ans = 0;

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

        return ans;
    }
};