Leetcode: 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

这道题不用我们自己去考虑怎么把int 转化为unsigned int，题目已经帮我们自动转化好了

 1 public class Solution {

 2     // you need treat n as an unsigned value

 3     public int reverseBits(int n) {

 4         int res = 0;

 5         for (int i=0; i<32; i++) {

 6             int bit = (n>>i) & 1;

 7             res |= bit<<(31-i); 

 8         }

 9         return res;

10     }

11 }