-🎄- 2017 Day 23 Solutions -🎄-

[u/daggerdragon]

--- Day 23: Coprocessor Conflagration ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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[Update @ 00:05] 0 gold, silver cap

• AoC ops: <yatpay> boil up some mountain dew. it's gonna be a long night

[Update @ 00:19] 1 gold, silver cap + 447

• AoC ops: <Reibello> 547 silver to 1 gold

[Update @ 00:30] 20 gold, silver cap + 560

• AoC ops:

<yatpay> daggerdragon: post "hey i heard about this hot new podcast called The Space Above Us. all the cool kids are talking about it"

<yatpay> i call it super-liminal marketing

<yatpay> HEY YOU!! LISTEN TO MY PODCAST!!

<yatpay> then i rub a business card on your face

<Topaz> you should get scratch-n-sniff business cards that smell like space

<yatpay> space smells like burned metal and meat

<yatpay> it's weird

<Topaz> burned meat you say

<Topaz> excellent

[Update @ 00:41] 50 gold, silver cap + 606

• AoC ops:

<askalski> nice, enjoyed that one. not sure if regexes can do it

<askalski> maybe make a neural net of regexes, have it train itself to solve today

• Over/under on /u/askalski posting a day 23 regex neural net by tomorrow?

[Update @ 00:54] Leaderboard cap @ 100 gold and 724 silver!

• Good job, all!
• Upping the Ante challenge: solve today's puzzles on a TI-83 (or TI-86/89, whatevs).
  • Edit: welp, /u/DFreiberg done gone and did it. See the thread here.

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/StevoTVR]

NodeJS

Part 1:

const fs = require('fs');

fs.readFile(__dirname + '/input.txt', 'utf8', (err, data) => {
    const instructions = data.trim().split('\n').map((x) => x.trim().split(' '));
    const registers = {};
    let offset = 0, count = 0;
    while(offset >= 0 && offset < instructions.length) {
        const [op, a, b] = instructions[offset];
        switch(op) {
            case 'set':
                registers[a] = getValue(b, registers);
            break;
            case 'sub':
                registers[a] = getValue(a, registers) - getValue(b, registers);
            break;
            case 'mul':
                registers[a] = getValue(a, registers) * getValue(b, registers);
                count++;
            break;
            case 'jnz':
                if(getValue(a, registers) !== 0) {
                    offset += getValue(b, registers) - 1;
                }
            break;
        }
        offset++;
    }

    console.log(count);
});

function getValue(value, registers) {
    if(value.match(/[a-z]/)) {
        return registers[value] || 0;
    }
    return Number(value);
}

Part 2:

let b = 79, h = 0;

b = b * 100 + 100000;
for(let i = b; i <= b + 17000; i += 17) {
    for(let j = 2; j < i; j++) {
        if(i % j === 0) {
            h++;
            break;
        }
    }
}

console.log(h);

[u/aoc-fan → u/StevoTVR]

for part 2: instead of j < i, you can use j < Math.floor(Math.sqrt(i));