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Josh Creek
38 lines
1.0 KiB
Plaintext
38 lines
1.0 KiB
Plaintext
--- Part Two ---
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Next, you need to find the largest basins so you know what areas are most important to avoid.
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A basin is all locations that eventually flow downward to a single low point. Therefore, every low point has a basin, although some basins are very small. Locations of height 9 do not count as being in any basin, and all other locations will always be part of exactly one basin.
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The size of a basin is the number of locations within the basin, including the low point. The example above has four basins.
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The top-left basin, size 3:
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2199943210
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3987894921
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9856789892
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8767896789
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9899965678
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The top-right basin, size 9:
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2199943210
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3987894921
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9856789892
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8767896789
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9899965678
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The middle basin, size 14:
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2199943210
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3987894921
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9856789892
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8767896789
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9899965678
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The bottom-right basin, size 9:
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2199943210
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3987894921
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9856789892
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8767896789
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9899965678
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Find the three largest basins and multiply their sizes together. In the above example, this is 9 * 14 * 9 = 1134.
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What do you get if you multiply together the sizes of the three largest basins? |