476. Number Complement

将整数的二进制逐位反转：每位与1异或即可，可完成反转

class Solution {
public:
    int findComplement(int num) {
        if(num==0)
            return 1;
        int flag=num,temp=1;
        while(flag)
        {
            flag=flag>>1;
            num=num^temp;
            temp=temp<<1;
        }
        return num;
    }
};