leetcode 190. Reverse Bits （int）数字旋转 ---------- java

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).

 

要求将一个无符号数进行二进制旋转，简单的位操作即可。。

 

public class Solution {
    // you need treat n as an unsigned value
    public int reverseBits(int n) {
        int result = 0;
        for (int i = 0; i < 32; i++){
            result = result | (((n >> i & 1) << (31 - i)));
        }
        return result;
    }
}

 

 

也可以优化一下。

public int reverseBits(int n) {
    if (n == 0) return 0;
    
    int result = 0;
    for (int i = 0; i < 32; i++) {
        result <<= 1;
        if ((n & 1) == 1) result++;
        n >>= 1;
    }
    return result;
}