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comparison 2017/day23/problem @ 34:049fb8e56025
Add problem statements and inputs
| author | Jordi Gutiérrez Hermoso <jordigh@octave.org> |
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| date | Tue, 09 Jan 2018 21:51:44 -0500 |
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| 33:bc652fa0a645 | 34:049fb8e56025 |
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| 1 --- Day 23: Coprocessor Conflagration --- | |
| 2 | |
| 3 You decide to head directly to the CPU and fix the printer from there. | |
| 4 As you get close, you find an experimental coprocessor doing so much | |
| 5 work that the local programs are afraid it will halt and catch fire. | |
| 6 This would cause serious issues for the rest of the computer, so you | |
| 7 head in and see what you can do. | |
| 8 | |
| 9 The code it's running seems to be a variant of the kind you saw | |
| 10 recently on that tablet. The general functionality seems very similar, | |
| 11 but some of the instructions are different: | |
| 12 | |
| 13 set X Y sets register X to the value of Y. | |
| 14 | |
| 15 sub X Y decreases register X by the value of Y. | |
| 16 | |
| 17 mul X Y sets register X to the result of multiplying the value | |
| 18 contained in register X by the value of Y. | |
| 19 | |
| 20 jnz X Y jumps with an offset of the value of Y, but only if the | |
| 21 value of X is not zero. (An offset of 2 skips the next | |
| 22 instruction, an offset of -1 jumps to the previous instruction, | |
| 23 and so on.) | |
| 24 | |
| 25 Only the instructions listed above are used. The eight registers | |
| 26 here, named a through h, all start at 0. | |
| 27 | |
| 28 The coprocessor is currently set to some kind of debug mode, which | |
| 29 allows for testing, but prevents it from doing any meaningful work. | |
| 30 | |
| 31 If you run the program (your puzzle input), how many times is the mul | |
| 32 instruction invoked? | |
| 33 | |
| 34 Your puzzle answer was 3025. | |
| 35 | |
| 36 --- Part Two --- | |
| 37 | |
| 38 Now, it's time to fix the problem. | |
| 39 | |
| 40 The debug mode switch is wired directly to register a. You flip the | |
| 41 switch, which makes register a now start at 1 when the program is | |
| 42 executed. | |
| 43 | |
| 44 Immediately, the coprocessor begins to overheat. Whoever wrote this | |
| 45 program obviously didn't choose a very efficient implementation. | |
| 46 You'll need to optimize the program if it has any hope of completing | |
| 47 before Santa needs that printer working. | |
| 48 | |
| 49 The coprocessor's ultimate goal is to determine the final value left | |
| 50 in register h once the program completes. Technically, if it had | |
| 51 that... it wouldn't even need to run the program. | |
| 52 | |
| 53 After setting register a to 1, if the program were to run to | |
| 54 completion, what value would be left in register h? | |
| 55 | |
| 56 Your puzzle answer was 915. | |
| 57 | |
| 58 Both parts of this puzzle are complete! They provide two gold stars: ** |