Capital One Senior+ Software Engineer Interview Experience — A Tetris-Style Grid Placement OA Question

There's an n x m grid of squares, and I need to draw a pattern on it. The pattern is made up of several fixed block shapes, kind of like Tetris. The problem gave 5 figure types: A, B, C, D, E.

For A: in a 2x2 square, it only occupies the top-left, top-right, and bottom-left cells. So A is:

[1, 0, 1]
[1, 1, 1]

That is, a U-shape / concave shape with the top-middle cell empty. This should go by the example matrix — for this kind of CodeSignal question, you usually go by however the shapes are defined in the problem body.

A [[1]]
B [[1, 1, 1]]
C [[1, 1],
   [1, 1]]
D [[1, 0],
   [1, 1],
   [1, 0]]
E [[0, 1, 0],
   [1, 1, 1]]

You return an n x m integer matrix, grid. Rules:

1. It starts out all 0.
2. After the i-th shape is placed, fill the cells it occupies with the number i+1.
3. Cells where nothing fits stay 0.

My rough approach was, for each figure: enumerate its possible top-left positions (r, c), check whether it can be placed there, find the first valid position, and fill the corresponding cells with the current figure's number.