476. Number Complement

The complement of an integer is the integer you get when you flip all the 0‘s to 1‘s and all the 1‘s to 0‘s in its binary representation.

• For example, The integer 5 is "101" in binary and its complement is "010" which is the integer 2.

Given an integer num, return its complement.

class Solution {
public:
    int findComplement(int num) {
        long long res = 0, po = 1;
        while(num) {
            if(num % 2 == 0) res += po;
            num /= 2;
            po *= 2;
        }
        return res;
    }
};