You need to change one thing on L142

From:

vector<int>temp=m[{x1,y1}];

To:

vector<int>& temp=m[{x1,y1}];

The first one copies the vector in m[{x1,y1}] to create a new vector stored in temp. This takes $$$O(n)$$$ time, where $$$n$$$ is the length of the vector.