HappyLeetcode58: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 as00111001011110000010100101000000).

Follow up:
If this function is called many times, how would you optimize it?

Related problem: Reverse Integer

Credits:
Special thanks to
@ts for adding this problem and creating all test cases.

这道题的难度不大,主要是位运算。因为是无符号数,所以我可以放心的让原数据右移,新数据得到新的一位之后进行左移。最终得到结果。对与有符号数,方法亦然。

代码如下:

class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
        uint32_t result = 0;
        int bit;
        for (int i = 0; i < 32; ++i)
        {
            bit = n & 0x01;
            n >>= 1;
            result <<= 1;
            result = result | bit;
        }
        return result;
    }
};

值得一提的是, >>=和<<=这两个符号之前基本上就没有用过,所以第一次写代码的时候漏掉了=号,今后注意。

posted @ 2015-03-09 13:30  程序员小王  阅读(119)  评论(0编辑  收藏  举报