题目链接：https://leetcode.com/problems/number-complement/#/description
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. class Solution { public: int findComplement(int num) { unsigned mask=~0; while(num& mask) mask<<=1; return ~mask & ~num; } };