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

https://leetcode.com/problems/number-complement/description/

python 中~操作是取补码, 此题取反

class Solution(object):def findComplement(self, num):""":type num: int:rtype: int"""return num ^ int(bin(num)[2:].replace("0","1"),2)

求没有前导0的正数反码值

class Solution {public int findComplement(int num) {String s = Integer.toBinaryString(num);int result = 0;for (int i = s.length() - 1; i >= 0; i--) {if (s.charAt(i) == '0') {result += Math.pow(2, s.length() - 1 - i);}}return result;}}