149 lines
5.5 KiB
Plaintext
149 lines
5.5 KiB
Plaintext
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Advent of Code
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--- Day 14: Space Stoichiometry ---
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As you approach the rings of Saturn, your ship's low fuel indicator turns on. There isn't any fuel here, but the rings have
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plenty of raw material. Perhaps your ship's Inter-Stellar Refinery Union brand nanofactory can turn these raw materials into
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fuel.
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You ask the nanofactory to produce a list of the reactions it can perform that are relevant to this process (your puzzle
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input). Every reaction turns some quantities of specific input chemicals into some quantity of an output chemical. Almost
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every chemical is produced by exactly one reaction; the only exception, ORE, is the raw material input to the entire process
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and is not produced by a reaction.
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You just need to know how much ORE you'll need to collect before you can produce one unit of FUEL.
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Each reaction gives specific quantities for its inputs and output; reactions cannot be partially run, so only whole integer
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multiples of these quantities can be used. (It's okay to have leftover chemicals when you're done, though.) For example, the
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reaction 1 A, 2 B, 3 C => 2 D means that exactly 2 units of chemical D can be produced by consuming exactly 1 A, 2 B and 3 C.
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You can run the full reaction as many times as necessary; for example, you could produce 10 D by consuming 5 A, 10 B, and 15
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C.
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Suppose your nanofactory produces the following list of reactions:
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10 ORE => 10 A
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1 ORE => 1 B
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7 A, 1 B => 1 C
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7 A, 1 C => 1 D
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7 A, 1 D => 1 E
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7 A, 1 E => 1 FUEL
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The first two reactions use only ORE as inputs; they indicate that you can produce as much of chemical A as you want (in
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increments of 10 units, each 10 costing 10 ORE) and as much of chemical B as you want (each costing 1 ORE). To produce 1
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FUEL, a total of 31 ORE is required: 1 ORE to produce 1 B, then 30 more ORE to produce the 7 + 7 + 7 + 7 = 28 A (with 2 extra
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A wasted) required in the reactions to convert the B into C, C into D, D into E, and finally E into FUEL. (30 A is produced
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because its reaction requires that it is created in increments of 10.)
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Or, suppose you have the following list of reactions:
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9 ORE => 2 A
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8 ORE => 3 B
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7 ORE => 5 C
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3 A, 4 B => 1 AB
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5 B, 7 C => 1 BC
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4 C, 1 A => 1 CA
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2 AB, 3 BC, 4 CA => 1 FUEL
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The above list of reactions requires 165 ORE to produce 1 FUEL:
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• Consume 45 ORE to produce 10 A.
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• Consume 64 ORE to produce 24 B.
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• Consume 56 ORE to produce 40 C.
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• Consume 6 A, 8 B to produce 2 AB.
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• Consume 15 B, 21 C to produce 3 BC.
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• Consume 16 C, 4 A to produce 4 CA.
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• Consume 2 AB, 3 BC, 4 CA to produce 1 FUEL.
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Here are some larger examples:
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• 13312 ORE for 1 FUEL:
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157 ORE => 5 NZVS
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165 ORE => 6 DCFZ
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44 XJWVT, 5 KHKGT, 1 QDVJ, 29 NZVS, 9 GPVTF, 48 HKGWZ => 1 FUEL
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12 HKGWZ, 1 GPVTF, 8 PSHF => 9 QDVJ
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179 ORE => 7 PSHF
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177 ORE => 5 HKGWZ
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7 DCFZ, 7 PSHF => 2 XJWVT
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165 ORE => 2 GPVTF
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3 DCFZ, 7 NZVS, 5 HKGWZ, 10 PSHF => 8 KHKGT
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• 180697 ORE for 1 FUEL:
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2 VPVL, 7 FWMGM, 2 CXFTF, 11 MNCFX => 1 STKFG
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17 NVRVD, 3 JNWZP => 8 VPVL
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53 STKFG, 6 MNCFX, 46 VJHF, 81 HVMC, 68 CXFTF, 25 GNMV => 1 FUEL
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22 VJHF, 37 MNCFX => 5 FWMGM
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139 ORE => 4 NVRVD
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144 ORE => 7 JNWZP
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5 MNCFX, 7 RFSQX, 2 FWMGM, 2 VPVL, 19 CXFTF => 3 HVMC
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5 VJHF, 7 MNCFX, 9 VPVL, 37 CXFTF => 6 GNMV
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145 ORE => 6 MNCFX
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1 NVRVD => 8 CXFTF
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1 VJHF, 6 MNCFX => 4 RFSQX
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176 ORE => 6 VJHF
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• 2210736 ORE for 1 FUEL:
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171 ORE => 8 CNZTR
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7 ZLQW, 3 BMBT, 9 XCVML, 26 XMNCP, 1 WPTQ, 2 MZWV, 1 RJRHP => 4 PLWSL
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114 ORE => 4 BHXH
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14 VRPVC => 6 BMBT
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6 BHXH, 18 KTJDG, 12 WPTQ, 7 PLWSL, 31 FHTLT, 37 ZDVW => 1 FUEL
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6 WPTQ, 2 BMBT, 8 ZLQW, 18 KTJDG, 1 XMNCP, 6 MZWV, 1 RJRHP => 6 FHTLT
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15 XDBXC, 2 LTCX, 1 VRPVC => 6 ZLQW
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13 WPTQ, 10 LTCX, 3 RJRHP, 14 XMNCP, 2 MZWV, 1 ZLQW => 1 ZDVW
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5 BMBT => 4 WPTQ
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189 ORE => 9 KTJDG
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1 MZWV, 17 XDBXC, 3 XCVML => 2 XMNCP
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12 VRPVC, 27 CNZTR => 2 XDBXC
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15 KTJDG, 12 BHXH => 5 XCVML
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3 BHXH, 2 VRPVC => 7 MZWV
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121 ORE => 7 VRPVC
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7 XCVML => 6 RJRHP
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5 BHXH, 4 VRPVC => 5 LTCX
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Given the list of reactions in your puzzle input, what is the minimum amount of ORE required to produce exactly 1 FUEL?
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Your puzzle answer was 751038.
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--- Part Two ---
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After collecting ORE for a while, you check your cargo hold: 1 trillion (1000000000000) units of ORE.
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With that much ore, given the examples above:
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• The 13312 ORE-per-FUEL example could produce 82892753 FUEL.
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• The 180697 ORE-per-FUEL example could produce 5586022 FUEL.
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• The 2210736 ORE-per-FUEL example could produce 460664 FUEL.
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Given 1 trillion ORE, what is the maximum amount of FUEL you can produce?
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Your puzzle answer was 2074843.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, all that is left is for you to admire your Advent calendar.
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If you still want to see it, you can get your puzzle input.
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References
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Visible links
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. https://adventofcode.com/
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. https://adventofcode.com/2019/about
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. https://adventofcode.com/2019/events
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. https://adventofcode.com/2019/settings
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. https://adventofcode.com/2019/auth/logout
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. Advent of Code Supporter
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https://adventofcode.com/2019/support
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. https://adventofcode.com/2019
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. https://adventofcode.com/2019
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. https://adventofcode.com/2019/support
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. https://adventofcode.com/2019/sponsors
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. https://adventofcode.com/2019/leaderboard
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. https://adventofcode.com/2019/stats
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. https://adventofcode.com/2019/sponsors
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. https://adventofcode.com/2019
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. https://adventofcode.com/2019/day/14/input
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