题目：

题解：

class Solution {
public:int findComplement(int num) {int highbit = 0;for (int i = 1; i <= 30; ++i) {if (num >= (1 << i)) {highbit = i;}else {break;}            }int mask = (highbit == 30 ? 0x7fffffff : (1 << (highbit + 1)) - 1);return num ^ mask;}
};