Unvectorize Column-Major

Problem

Rebuild a rows x cols matrix from a flat vector stored in column-major order.

Column 0 occupies the first rows entries of vec, column 1 the next rows entries, and so on.

Hint

Entry (i, j) lives at index j * rows + i in the flat vector.

case 1

in: [[1,3,2,4],2,2]

expected: [[1,2],[3,4]]

case 2

in: [[1,2,3],1,3]

expected: [[1,2,3]]

case 3

in: [[1,2,3],3,1]

expected: [[1],[2],[3]]

case 4

in: [[1,3,5,2,4,6],3,2]

expected: [[1,2],[3,4],[5,6]]

Starter codePython

def unvectorize_column_major(vec, rows, cols):
    # Your code here
    pass

4 test cases · run your code against them in the editor