Convert to Base -2 Solutions in C++

/// Source : https://leetcode.com/problems/convert-to-base-2/
/// Author : liuyubobobo
/// Time   : 2019-03-30

#include <iostream>

using namespace std;


/// Mathematics
/// Time Complexity: O(logn)
/// Space Complexity: O(1)
class Solution {
public:
    string baseNeg2(int N) {

        string res = "";
        while(N){
            if(abs(N) % 2) res += "1";
            else res += "0";

            if(abs(N) % 2) N --;
            N /= -2;
        }

        reverse(res.begin(), res.end());
        return res.size() ? res : "0";
    }
};


int main() {

    return 0;
}