Given a vector<vector<int>> and a value x, return the positions of all matching elements, as an vector<vector<int>>. If x is not found, return [[-1, -1]].
vector<vector<int>> and a value x, return the positions of all matching elements, as an vector<vector<int>>. If x is not found, return [[-1, -1]].
x
vector<vector<int>>. If x is not found, return [[-1, -1]].
[[-1, -1]]