Binary Gap

<-E 868> Binary Gap

class Solution {
public:
    int binaryGap(int n) {
        string str = bitset<64>(n).to_string();
        int dist = 0, pre = -1;
        for (auto i = 0; i < 64; i++)
        {
            if (str[i] != '0')
            {
                if (pre == -1)
                    pre = i;
                else
                    dist = max(dist, i - pre), pre = i;
            }
        }
        return dist;
    }
};