class Solution {
public:
int countBinarySubstrings(string s) {
vector<int> res;
int tol = 1;
for (int i=1; i<=s.length(); i++) {
if (s[i]==s[i-1]) {
tol++;
}else{
res.push_back(tol);
tol =1;
}
}
int count = 0;
for(int i=1, n=res.size(); i<n; ++i){
count += min(res[i-1], res[i]);
}
return count;
}
};
