Binary Watch

class Solution {
public:
    int next(int num)
    {
        int last = num&(-num);
        int hi = num+last;
        int lowerOrigShiftd = ((hi)^num)/last;
        lowerOrigShiftd >>= 2;
        return hi|lowerOrigShiftd;
    }
    vector<string> readBinaryWatch(int num) {
        if(num == 0) return {"0:00"};
        int n = 0;
        while(num)
        {
            num--;
            n = (n<<1)|1;
        }
        vector<string> res;
        while((n>>6) <= 0x1011)
        {
            int hr = n/64;
            int min = n%64;
            n = next(n);
            if((hr >= 12) or (min >= 60)) continue;
            string ans = to_string(hr)+":"+(min/10==0?"0":"")+to_string(min);
            res.push_back(ans);
        }
        return res;
    }
};