what is the weight of minimum -weight spanning tree in the graph ?

Question

I tried by taking n=2 , and took points (1,1) ,(1,2) ,(2,2),(2,1) and I got the minimum weight to be 3 , which is n+1 but according to answer it is n-1 

Answer 1

The length of an MST (number of edges required to make it) in an nXn grid where each square is a vertex is always n^2-1 ...(1)

Further, if an edge is axial (vertical or horizontal), then its weight should be 1 according to the formula given in the problem. ...(2)

 

Now since we are taking only axial edges, the total weight of the MST from (1) & (2) comes out to be: (n^2-1)*1

So the weight of the MST of this graph should be n^2-1 according to me.