476. 數字的補數 Number Complement

題目 https://leetcode-cn.com/problems/number-complement/submissions/

int findComplement(int num){
	int i = -1 - num;
	int j = num,k;
	while(j != 0){
		k = j;
		j &= (j-1);
	}
	return i&(k-1);
}