Leetcode练习 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.

求各位取反后的数，直接用not会把前面的位数都算上。。。这边用了一个highestOneBit函数，直接返回最大1所在的位置的数

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