Given a matrix X (Dimensions: N *C). Now using matrix multiplication, get a new matrix of the same size.

In this new matrix for each row only one element remains same and the rest have been made 0.

The elements which remains the same are chosen by a vector which tells the column position of such elements.

Vector y has dimensions : N*1

How to find the other element which when multiplied by X gives the correct answer.

eg X = [[1,2],[3,4],[5,6]]

y = [1,0,1]

New Matrix = X*M = [[0,2],[3,0],[0,6]]

Find M?