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Add problem statements and inputs
author Jordi Gutiérrez Hermoso <jordigh@octave.org>
date Tue, 09 Jan 2018 21:51:44 -0500
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Jordi Gutiérrez Hermoso <jordigh@octave.org>
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1 --- Day 23: Coprocessor Conflagration ---
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2
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3 You decide to head directly to the CPU and fix the printer from there.
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4 As you get close, you find an experimental coprocessor doing so much
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5 work that the local programs are afraid it will halt and catch fire.
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6 This would cause serious issues for the rest of the computer, so you
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7 head in and see what you can do.
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8
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9 The code it's running seems to be a variant of the kind you saw
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10 recently on that tablet. The general functionality seems very similar,
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11 but some of the instructions are different:
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12
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13 set X Y sets register X to the value of Y.
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14
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15 sub X Y decreases register X by the value of Y.
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16
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17 mul X Y sets register X to the result of multiplying the value
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18 contained in register X by the value of Y.
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19
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20 jnz X Y jumps with an offset of the value of Y, but only if the
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21 value of X is not zero. (An offset of 2 skips the next
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22 instruction, an offset of -1 jumps to the previous instruction,
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23 and so on.)
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24
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25 Only the instructions listed above are used. The eight registers
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26 here, named a through h, all start at 0.
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27
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28 The coprocessor is currently set to some kind of debug mode, which
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29 allows for testing, but prevents it from doing any meaningful work.
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30
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31 If you run the program (your puzzle input), how many times is the mul
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32 instruction invoked?
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33
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34 Your puzzle answer was 3025.
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35
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36 --- Part Two ---
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37
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38 Now, it's time to fix the problem.
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39
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40 The debug mode switch is wired directly to register a. You flip the
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41 switch, which makes register a now start at 1 when the program is
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42 executed.
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43
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44 Immediately, the coprocessor begins to overheat. Whoever wrote this
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45 program obviously didn't choose a very efficient implementation.
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46 You'll need to optimize the program if it has any hope of completing
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47 before Santa needs that printer working.
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48
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49 The coprocessor's ultimate goal is to determine the final value left
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50 in register h once the program completes. Technically, if it had
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51 that... it wouldn't even need to run the program.
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52
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53 After setting register a to 1, if the program were to run to
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54 completion, what value would be left in register h?
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55
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56 Your puzzle answer was 915.
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57
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58 Both parts of this puzzle are complete! They provide two gold stars: **