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Mark my beacons

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Given a grid of numbers, mark the concentric areas around nonzero elements (beacons) decreasing from the value of the beacon till 1.

For example, here are some grids with a single beacon:

Size 1:

0 0 0    0 0 0
0 1 0 -> 0 1 0
0 0 0    0 0 0

Size 2:

0 0 0    1 1 1
0 2 0 -> 1 2 1
0 0 0    1 1 1

Size 3:

0 0 0 0 0    1 1 1 1 1
0 0 0 0 0    1 2 2 2 1
0 0 3 0 0 -> 1 2 3 2 1
0 0 0 0 0    1 2 2 2 1
0 0 0 0 0    1 1 1 1 1

I/O

Your input is in the form of a 2D grid of integers. You can take the dimensions if needed.

Your output can have multiple beacons of various sizes.
If beacons overlap, you can overwrite one full beacon over the other. You can choose which beacon takes priority.
beacons can be on the edges of the grid. they will not wrap around.

Tests

Test 1: JSON Array

Input:
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 4
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0 0
0 0 0 2 0 0 1 0 0 0
0 0 0 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
Output:
0 0 0 0 0 0 1 2 3 3
0 0 0 0 0 0 1 2 3 4
0 0 0 0 0 0 1 2 3 3
1 1 0 0 0 0 1 2 2 2
2 1 1 1 1 0 1 1 1 1
1 1 1 2 1 0 1 0 0 0
0 0 1 1 1 0 0 0 0 0
0 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0

Test 2: JSON Array

Input:
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 4 0 0 0 0
0 0 4 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 3 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Output:
1 1 1 1 1 1 0 1 2 2 2 2 2 1 0
2 2 2 2 2 1 0 1 2 3 3 3 2 1 0
2 3 3 3 2 1 0 1 2 3 4 3 2 1 0
2 3 4 3 2 1 0 1 2 3 3 3 2 1 0
2 3 3 3 2 1 0 1 2 2 2 2 2 1 0
2 2 2 2 2 1 0 1 1 1 1 1 1 1 0
1 1 1 1 1 1 0 0 0 0 0 0 0 0 0
1 2 2 2 1 0 0 0 0 0 0 0 0 0 0
1 2 3 2 1 0 0 0 0 0 0 0 0 0 0
1 2 2 2 1 0 0 0 0 0 0 0 0 0 0

Test 3: JSON Array

Input:
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 3 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 3 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
All possible outputs:
1 1 1 1 1 0 0 0
1 2 2 2 1 0 0 0
1 2 1 1 1 1 1 0
1 2 1 2 2 2 1 0
1 1 1 2 3 2 1 0
0 0 1 2 2 2 1 0
0 0 1 1 1 1 1 0
0 0 0 0 0 0 0 0
---
1 1 1 1 1 0 0 0
1 2 2 2 1 0 0 0
1 2 3 2 1 1 1 0
1 2 2 2 1 2 1 0
1 1 1 1 1 2 1 0
0 0 1 2 2 2 1 0
0 0 1 1 1 1 1 0
0 0 0 0 0 0 0 0

code-golf matrix

posted over 2 years ago

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1 comment thread

Include a test with overlapping beacons (8 comments)

trichoplax‭ wrote over 2 years ago

From "You can choose which one takes priority." I assume that for 2 overlapping beacons there are only 2 potential solutions.

That is, one beacon must be chosen to entirely overwrite the other everywhere that they overlap.

In case anyone has a different interpretation, such as giving priority to different beacons in different parts of the output (for example always choosing the higher of the 2 numbers that could be placed at each position), it might be useful to explicitly indicate one interpretation or the other before any more answers come in.

trichoplax‭ wrote over 2 years ago · edited over 2 years ago

Illustration of the example:

I suspect this was not intended to be a valid output but it would be good to have it made explicit either way.