[LeetCode] Reverse Bits

Question：

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?

1、题型分类：

2、思路：

3、时间复杂度：

4、代码：

public class Solution {
    // you need treat n as an unsigned value
    public int reverseBits(int n) {
        int i=0,result=0;
        while(i<32)
        {
            result=(result<<1)|(n&1);
            n=n>>1;
            i++;
        }
        return result;
    }
}

　　注意加粗部分，先移位还是先或的区别！

5、优化：

6、扩展：