45 lines
2.1 KiB
Plaintext
45 lines
2.1 KiB
Plaintext
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--- Day 3: Spiral Memory ---
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You come across an experimental new kind of memory stored on an infinite two-dimensional grid.
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Each square on the grid is allocated in a spiral pattern starting at a location marked 1 and then counting up while spiraling outward. For example, the first few squares are allocated like this:
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17 16 15 14 13
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18 5 4 3 12
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19 6 1 2 11
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20 7 8 9 10
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21 22 23---> ...
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While this is very space-efficient (no squares are skipped), requested data must be carried back to square 1 (the location of the only access port for this memory system) by programs that can only move up, down, left, or right. They always take the shortest path: the Manhattan Distance between the location of the data and square 1.
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For example:
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Data from square 1 is carried 0 steps, since it's at the access port.
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Data from square 12 is carried 3 steps, such as: down, left, left.
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Data from square 23 is carried only 2 steps: up twice.
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Data from square 1024 must be carried 31 steps.
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How many steps are required to carry the data from the square identified in your puzzle input all the way to the access port?
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--- Part Two ---
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As a stress test on the system, the programs here clear the grid and then store the value 1 in square 1. Then, in the same allocation order as shown above, they store the sum of the values in all adjacent squares, including diagonals.
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So, the first few squares' values are chosen as follows:
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Square 1 starts with the value 1.
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Square 2 has only one adjacent filled square (with value 1), so it also stores 1.
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Square 3 has both of the above squares as neighbors and stores the sum of their values, 2.
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Square 4 has all three of the aforementioned squares as neighbors and stores the sum of their values, 4.
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Square 5 only has the first and fourth squares as neighbors, so it gets the value 5.
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Once a square is written, its value does not change. Therefore, the first few squares would receive the following values:
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147 142 133 122 59
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304 5 4 2 57
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330 10 1 1 54
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351 11 23 25 26
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362 747 806---> ...
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What is the first value written that is larger than your puzzle input?
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