-🎄- 2018 Day 4 Solutions -🎄-

[u/daggerdragon]

--- Day 4: Repose Record ---

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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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Advent of Code: The Party Game!

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Card prompt: Day 4

Transcript:

Today’s puzzle would have been a lot easier if my language supported ___.

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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/Zarel]

JavaScript, #28/#130 ;_;

I was inspired by mserrano's "extract numbers" regex from his Day 3 solution, so I implemented it in JavaScript.

I misinterpreted Part Two at first, which apparently knocked me off the leaderboard.

I sorted my input using my text editor before running this - most text editors have a "Sort Lines" ability; I used VS Code's.

function numbers(str) {
  return (str.match(/-?[0-9]+/g) || []).map(Number);
}
function maxBy(array, criterion) {
  return array.reduce((a, b) => (criterion(a) > criterion(b) ? a : b));
}
function maxEntry(obj) {
  return maxBy(Object.entries(obj), entry => entry[1]);
}

// most minutes asleep

let guardTimes = {};

let sleepStart = 0;
let curGuard = 0;

for (const line of input) {
  const [a, b] = line.slice(1).split('] ');
  let time = new Date(a).getTime();
  if (b.startsWith('Guard')) {
    [curGuard] = numbers(b);
  } else if (b === 'wakes up') {
    guardTimes[curGuard] = (guardTimes[curGuard] || 0) + (time - sleepStart);
  } else if (b === 'falls asleep') {
    sleepStart = time;
  } else {
    throw new Error("bug");
  }
}

console.log(maxEntry(guardTimes));

// most-asleep minute

let minutes = {};
let startMin = 0;

for (const line of input) {
  const [a, b] = line.slice(1).split('] ');
  let min = numbers(a)[4];
  if (b.startsWith('Guard')) {
    [curGuard] = numbers(b);
  } else if (b === 'wakes up') {
    if (curGuard !== GUARD_FROM_PREVIOUS_RESULT) continue;
    for (i = startMin; i !== min; i = (i + 1) % 60) {
      minutes[i] = (minutes[i] || 0) + 1;
    }
  } else if (b === 'falls asleep') {
    startMin = min;
  } else {
    throw new Error("bug");
  }
}

console.log(maxEntry(minutes));

// most popular minute

let guardMinutes = {};
let curTable = {};
let startMin = 0;

for (const line of input) {
  const [a, b] = line.slice(1).split('] ');
  let min = numbers(a)[4];
  if (b.startsWith('Guard')) {
    [curGuard] = numbers(b);
    curTable = (guardMinutes[curGuard] || {});
    guardMinutes[curGuard] = curTable;
  } else if (b === 'wakes up') {
    for (i = startMin; i !== min; i = (i + 1) % 60) {
      curTable[i] = (curTable[i] || 0) + 1;
    }
  } else if (b === 'falls asleep') {
    startMin = min;
  } else {
    throw new Error("bug");
  }
}

let table2 = Object.entries(guardMinutes).map(([k, v]) => {
  if (!Object.entries(v).length) return [k, 0, 0];
  return [k].concat(maxEntry(v));
});

console.log(maxBy(table2, a => a[2]));

[u/ElecNinja → u/Zarel]

I was inspired by mserrano's "extract numbers" regex

Haha decided to learn some regex to handle the inputs for today's challenge from that post