leetcode 190

Posted 2020-08-18

190. 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?

Related problem: Reverse Integer

按位翻转输入的整数。

代码如下：

 

 1 class Solution {
 2 public:
 3     uint32_t reverseBits(uint32_t n) {
 4         unsigned ret = 0;
 5         unsigned pos1 = 1 << 31;
 6         unsigned pos2 = 1;
 7         while(pos1)
 8         {
 9             if(pos1 & n)
10                 ret |= pos2;
11             pos2 <<= 1;
12             pos1 >>= 1;
13         }
14         return ret;
15     }
16 };