```
" BW "
" BW "
```

Given this board, the test expects (1, 1) and (1, 2) owned by black, and (4, 1) and (4, 2) owned by white. Are the coordinates (column, row) instead of (row, column), because this board doesn’t have 4 rows? Instructions say nothing about this.

Looks to me like *x*, -*y* coordinates.

```
1 2 3 4 x
1 ⋅ B W ⋅
2 ⋅ B W ⋅
y
```

I figured this out by comparing several tests with each other.

You’re right but while iterating on a 2D grid, (0, 0) is the top left corner, so, I won’t call it -y coordinates. The coordinates used by the tests are indeed (column, row), and in addition, 1-based. So, to translate those to 0-based indices, we need to swap the coordinates and subtract 1 from each component.

I call it *x*, -*y* because ‘ordinarily’ (YMMV) +*y* is up, but here it is down. I coined it just for that reply though.

Is there any remaining confusion?

No, except that another student might have the same question. Might help to state in the question.

I do not know who to ping for this.

The coordinate system varies between tracks. I do not know how to deal with that, and I’m not going to figure it out myself in the short term.