A number of bacteria lie on an infinite grid of cells, each bacterium in its own cell.
Each second, the following transformations occur (all simultaneously):
- If a bacterium has no neighbor to its north and no neighbor to its west, then it will die.
- If a cell has no bacterium in it, but there are bacteria in the neighboring cells to the north and to the west, then a new bacterium will be born in that cell.
Upon examining the grid, you note that there are a positive, finite number of bacteria in one or more rectangular regions of cells.
Determine how many seconds will pass before all the bacteria die.
Here is an example of a grid that starts with 6 cells containing bacteria, and takes 6 seconds for all the bacteria to die. '1's represent cells with bacteria, and '0's represent cells without bacteria.
000010
011100
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010000
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000110
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011000
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000010
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001100
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000010
000110
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000010
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