typedef pair<int, int> PII;

class Solution

{

public:

vector<int> kWeakestRows(vector<vector<int>>& mat, int k)

{

priority_queue<PII> q;

for (int i = 0; i < mat.size(); i++)

{

q.push({numOnes(mat[i]), i});

if (q.size() > k) q.pop();

}

vector<int> res(k);

for (int i = k - 1; ~i; i--)

{

res[i] = q.top().second;

q.pop();

}

return res;

}

private:

int numOnes(vector<int>& row)

{

int l = 0, r = row.size();

while (l < r)

{

int mid = (l + r) >> 1;

if (row[mid] == 1) l = mid + 1;

else r = mid;

}

return l;

}

};