LeetCode——476. Number Complement

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

Note:
The given integer is guaranteed to fit within the range of a 32-bit signed integer.
You could assume no leading zero bit in the integer’s binary representation.

Example 1:
Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.
Example 2:
Input: 1
Output: 0

Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.

public class Solution {public int findComplement(int num) {    return (Integer.highestOneBit(num)<<1)-1-num;}

}

!!!英语是真的难!!!

真，真的这个英文题目阅读能力真的是要提高。这个题目意思要的就是反码，complement一查是补码，结果根据题意就是反码 ：）反码 = 最大值 - 原码 highestOneBit(num) 是 Integer类的静态方法，返回num的第一个1的位置的二进制代码：比如 num = 5 = 101；那么方法返回就是100；    num = 12 = 1100；那么方法返回的就是1000；