andre's recent activity

Comment on What do you all think about HBO's The Last of Us show? - S1E1 Discussion in ~tv
andre
January 18
Link Parent
Oh rad! Thanks for letting me know.

Oh rad! Thanks for letting me know.

1 vote
Comment on What do you all think about HBO's The Last of Us show? - S1E1 Discussion in ~tv
andre
January 17
Link Parent
Definitely. I play a lot of PC games, but have less than zero interest in consoles, for many reasons. I've heard nothing but good things about the game, and I'm happy there's a TV adaptation as...

Definitely. I play a lot of PC games, but have less than zero interest in consoles, for many reasons. I've heard nothing but good things about the game, and I'm happy there's a TV adaptation as I'd otherwise never experience it.

1 vote
Comment on Verstappen bests Hamilton to claim first career world championship in ~sports
andre
December 12, 2021
Link
Lewis deserved the race win, Max deserved WDC.

Lewis deserved the race win, Max deserved WDC.

3 votes
Comment on Al Jazeera to launch rightwing media platform targeting US conservatives in ~news
andre
February 23, 2021
Link
I thought this was an Onion article at first, but sure enough... I can't see it taking off though - as soon as a righty realizes Rightly is owned by Al Jazeera, their hate of brown people will...

I thought this was an Onion article at first, but sure enough... I can't see it taking off though - as soon as a righty realizes Rightly is owned by Al Jazeera, their hate of brown people will make them change the channel.

7 votes
Comment on Need a laptop for school, budget $2000, details inside in ~tech
andre
February 7, 2021
Link Parent
As a counterpoint, when going to UT for computer science in the 2000s, I'd estimate a full 65% of students and 90% of faculty had MacBooks. (As a side note, despite tempest's resistance to Macs,...

As a counterpoint, when going to UT for computer science in the 2000s, I'd estimate a full 65% of students and 90% of faculty had MacBooks.

(As a side note, despite tempest's resistance to Macs, I'm going to join stu2b50 and recommend an M1 Air - I can't imagine picking that and ending up disappointed)

9 votes
Comment on Trump revokes rule preventing White House staff from lobbying in ~news
andre
January 20, 2021
Link Parent
That would require politicians to put the prosperity of the country above their donors.

That would require politicians to put the prosperity of the country above their donors.

1 vote
Comment on Are software engineers "engineers"? in ~comp
andre
January 20, 2021
Link Parent
I have a Bachelor of Arts in Computer Science from UT Austin - it actually used to be in both schools, with some of the non-CS elective classes being the differentiating factor.

I have a Bachelor of Arts in Computer Science from UT Austin - it actually used to be in both schools, with some of the non-CS elective classes being the differentiating factor.

1 vote
Comment on The scary power of the companies that finally shut Trump up in ~tech
andre
January 12, 2021
Link Parent
I agree: they're taking action based on a high level, long-term business strategy. Unless I misunderstood this entire thread, skybrian was arguing that we should give Twitter/Facebook the benefit...

I agree: they're taking action based on a high level, long-term business strategy.

Unless I misunderstood this entire thread, skybrian was arguing that we should give Twitter/Facebook the benefit of the doubt that they acted for the benefit of society instead of on a business calculus (which, ultimately, is a decision of what will create the most profit), which struck me as naive.

8 votes
Comment on The scary power of the companies that finally shut Trump up in ~tech
andre
January 12, 2021
Link Parent
If you don't think that Twitter and Facebook have spent substantial resources over the last four years attempting to asses the financial risk/reward of (de)platforming Trump, I don't think our...

If you don't think that Twitter and Facebook have spent substantial resources over the last four years attempting to asses the financial risk/reward of (de)platforming Trump, I don't think our dialogue will be productive.

He wasn't banned because Dorsey and Zuck suddenly grew consciences - these are corporations beholden to their stockholders and governmental regulations, and the calculus shifted such that banning him was the right business move.

My default thought pattern is that all of these people are greedy assholes, and whereas you need evidence that the decision was based on finances, I need evidence that it wasn't. Neither of us has this, so it's speculation all around.

11 votes
Comment on The scary power of the companies that finally shut Trump up in ~tech
andre
January 12, 2021
Link Parent
I agree that it's good to be cautious, but let's not be naive either.

I agree that it's good to be cautious, but let's not be naive either.

7 votes
Comment on Donald Trump response to yesterday violent roitious insurrection at the Capitol in ~news
andre
January 8, 2021
Link Parent
I liked Sam Harris' take on Twitter:

I liked Sam Harris' take on Twitter:

This Boston Dynamics Trump robot is amazing.

8 votes
Comment on Day 8: Handheld Halting in ~comp
andre
December 8, 2020
Link Parent
I didn't need to add anything special for part 2 - if you were stopping execution when you saw an instruction twice (from part 1), you shouldn't have hit any infinite loops. I actually thought the...

I didn't need to add anything special for part 2 - if you were stopping execution when you saw an instruction twice (from part 1), you shouldn't have hit any infinite loops. I actually thought the problem was well structured to have you implement that part first.

5 votes

Comment on Day 8: Handheld Halting in ~comp

andre

December 8, 2020

Link

JavaScript Parts 1 + 2 function parseInput(input) { let lines = input.split('\n').map(l => { const [, instr, param] = l.match(/(.*) (.*)/) return { instr, param: Number(param) } }) return lines }...

JavaScript

Parts 1 + 2

function parseInput(input) {
  let lines = input.split('\n').map(l => {
    const [, instr, param] = l.match(/(.*) (.*)/)
    return { instr, param: Number(param) }
  })

  return lines
}

function run(prog) {
  let ptr = 0
  let acc = 0
  let seen = []

  while (true) {
    if (!prog[ptr]) return { halts: true, acc }
    if (seen[ptr]) return { halts: false, acc }

    const { instr, param } = prog[ptr]
    seen[ptr] = true

    if (instr === 'jmp') {
      ptr += param
    }

    if (instr === 'acc') {
      acc += param
      ptr++
    }

    if (instr === 'nop') {
      ptr++
    }
  }
}

export function solvePart1(input) {
  let prog = parseInput(input)
  return run(prog).acc
}

export function solvePart2(input) {
  let prog = parseInput(input)

  for (let i = 0; i < prog.length; i++) {
    let { instr, param } = prog[i]

    if (instr.match(/(nop|jmp)/)) {
      const progCopy = [...prog]
      progCopy[i] = {
        instr: instr === 'nop' ? 'jmp' : 'nop',
        param,
      }

      const result = run(progCopy)
      if (result.halts) return result.acc
    }
  }
}

2 votes

Comment on Day 7: Handy Haversacks in ~comp

andre

December 7, 2020

Link

I was really unhappy with my original solution, so this is a refactored solution after thinking about it more clearly and taking some inspiration from Sophie Alpert. JS Parts 1+2 function...

I was really unhappy with my original solution, so this is a refactored solution after thinking about it more clearly and taking some inspiration from Sophie Alpert.

Parts 1+2

function parseInput(input) {
  const contains = {}
  const containedIn = {}

  input.split('\n').forEach(line => {
    let [, color, children] = line.match(/(.*) bags contain (.*)/)

    contains[color] = []
    for (let [, num, type] of children.matchAll(/(\d+) (.+?) bags?[,.]/g)) {
      contains[color].push({ num: Number(num), type })
      ;(containedIn[type] || (containedIn[type] = [])).push(color)
    }
  })

  return { contains, containedIn }
}

export function solvePart1(input) {
  let { containedIn } = parseInput(input)

  function containers(color, set = new Set()) {
    containedIn[color]?.forEach(c => {
      set.add(c)
      containers(c, set)
    })
    return set
  }

  return containers('shiny gold').size
}

export function solvePart2(input) {
  let { contains } = parseInput(input)

  function sumBags(root) {
    return 1 + _.sum(contains[root].map(c => c.num * sumBags(c.type)))
  }

  return sumBags('shiny gold') - 1
}

3 votes

Comment on Day 5: Binary Boarding in ~comp

andre

December 6, 2020

Link

JavaScript My initial implementation was a typical binary search and then straightforward id calculation. After reading some of the answers here and realizing it's just a binary number, here's a...

JavaScript

My initial implementation was a typical binary search and then straightforward id calculation. After reading some of the answers here and realizing it's just a binary number, here's a more interesting solution:

Parts 1 + 2

export function solvePart1(input) {
  input = input.split('\n')
  return _.max(
    input.map(seat => {
      return parseInt(seat.replace(/(F|L)/g, 0).replace(/(B|R)/g, 1), 2)
    }),
  )
}

export function solvePart2(input) {
  input = input.split('\n')

  const ids = input
    .map(seat => {
      return parseInt(seat.replace(/(F|L)/g, 0).replace(/(B|R)/g, 1), 2)
    })
    .sort((a, b) => a - b) // Array.sort() is lexicographical in JS, lol

  for (let i = 0; i < ids.length; i++) {
    if (ids[i] !== ids[0] + i) {
      return ids[0] + i
    }
  }
}

1 vote

Comment on <deleted topic> in ~comp
andre
December 5, 2020
Link Parent
If you want to see one of the consistent leaderboard finishers solve the puzzles live, check out Jonathan Paulson's YouTube channel.

If you want to see one of the consistent leaderboard finishers solve the puzzles live, check out Jonathan Paulson's YouTube channel.

6 votes

Comment on Day 4: Passport Processing in ~comp

andre

December 4, 2020

Link

I didn't start this one at release time, but it wouldn't have mattered - had a really annoying mistake that took a while to track down. Reasonably happy with the outcome though. JavaScript Parts 1...

I didn't start this one at release time, but it wouldn't have mattered - had a really annoying mistake that took a while to track down. Reasonably happy with the outcome though.

JavaScript

Parts 1 and 2

function isValid(p) {
  if (!p) return false

  if (p.byr < 1920 || p.byr > 2002) return false
  if (p.iyr < 2010 || p.iyr > 2020) return false
  if (p.eyr < 2020 || p.eyr > 2030) return false

  let [match, hgt, unit] = /(\d+)(cm|in)?/.exec(p.hgt)
  if (
    !match ||
    !unit ||
    (unit == 'cm' && (hgt < 150 || hgt > 193)) ||
    (unit == 'in' && (hgt < 59 || hgt > 76))
  ) {
    return false
  }

  if (!/^#[0-9a-f]{6}$/.test(p.hcl)) return false
  if (!/(amb|blu|brn|gry|grn|hzl|oth)/.test(p.ecl)) return false
  if (!/^\d{9}$/.test(p.pid)) return false

  return true
}

function Passport(line) {
  const requiredFields = ['byr', 'iyr', 'eyr', 'hgt', 'hcl', 'ecl', 'pid']

  const passport = line.split(' ').reduce((acc, field) => {
    const [key, value] = field.split(':')

    const idx = requiredFields.indexOf(key)
    if (idx > -1) requiredFields.splice(idx, 1)

    acc[key] = value
    return acc
  }, {})

  if (requiredFields.length) return null
  return passport
}

export function solvePart1(input) {
  input = input.split('\n\n').map(l => l.replace(/\n/g, ' '))
  return input.filter(Passport).length
}

export function solvePart2(input) {
  input = input.split('\n\n').map(l => l.replace(/\n/g, ' '))
  return input.map(Passport).filter(isValid).length
}

3 votes

Comment on Day 3: Toboggan Trajectory in ~comp

andre

December 3, 2020

Link

Nothing too special here, very similar to solution to most people I imagine. 858/576. Part 1 and 2 in JS function countTrees(path, dx, dy) { let y = 0 let x = 0 let trees = 0 while (y <...

Nothing too special here, very similar to solution to most people I imagine. 858/576.

Part 1 and 2 in JS

function countTrees(path, dx, dy) {
  let y = 0
  let x = 0
  let trees = 0

  while (y < path.length) {
    if (path[y][x] === '#') {
      trees++
    }

    x = (x + dx) % path[y].length
    y += dy
  }

  return trees
}

export function solvePart1(input) {
  input = input.split('\n')
  return countTrees(input, 3, 1)
}

export function solvePart2(input) {
  input = input.split('\n')

  const slopes = [
    [1, 1],
    [3, 1],
    [5, 1],
    [7, 1],
    [1, 2],
  ]

  return slopes.map(s => countTrees(input, ...s)).reduce((acc, t) => acc * t, 1)
}

2 votes

Comment on <deleted topic> in ~comp

andre

December 2, 2020

Link

I did 2017 and 2018 in JS, will be doing 2020 in the same. Here's my run harness and solutions. I'm happy with the workflow: run tests in watch mode (so they immediately execute when I save a file...

I did 2017 and 2018 in JS, will be doing 2020 in the same. Here's my run harness and solutions. I'm happy with the workflow: run tests in watch mode (so they immediately execute when I save a file in vim) while writing the answer, followed by yarn run solve 2020 02 1, which downloads the input from AoC, executes your solution, and puts the answer in your clipboard.

Day 01

export function solvePart1(input) {
  input = U.linesToNumbers(input)
  for (let i = 0; i < input.length; i++) {
    for (let k = 0; k < input.length; k++) {
      if (input[i] + input[k] === 2020) {
        return input[i] * input[k]
      }
    }
  }
}

export function solvePart2(input) {
  input = U.linesToNumbers(input)
  for (let i = 0; i < input.length; i++) {
    for (let j = 0; j < input.length; j++) {
      for (let k = 0; k < input.length; k++) {
        if (input[i] + input[k] + input[j] === 2020) {
          return input[i] * input[k] * input[j]
        }
      }
    }
  }
}

Day 02

export function solvePart1(input) {
  return input.split('\n').filter(line => {
    let [, min, max, letter, str] = /(\d+)-(\d+) (.): (.*)/.exec(line)
    min = Number(min)
    max = Number(max)

    const count = str.split('').filter(c => c === letter).length
    return count >= min && count <= max
  }).length
}

export function solvePart2(input) {
  return input.split('\n').filter(line => {
    let [, min, max, letter, str] = /(\d+)-(\d+) (.): (.*)/.exec(line)
    min = Number(min)
    max = Number(max)

    return U.xor(str[min - 1] === letter, str[max - 1] === letter)
  }).length
}

2 votes

Comment on <deleted topic> in ~comp
andre
December 2, 2020
Link Parent
I did 20/25 in 2018, skipped 2019, but am planning on giving it another go this year.

I did 20/25 in 2018, skipped 2019, but am planning on giving it another go this year.

5 votes

andre's recent activity

Comment on What do you all think about HBO's The Last of Us show? - S1E1 Discussion in ~tv

Comment on What do you all think about HBO's The Last of Us show? - S1E1 Discussion in ~tv

Comment on Verstappen bests Hamilton to claim first career world championship in ~sports

Comment on Al Jazeera to launch rightwing media platform targeting US conservatives in ~news

Comment on Need a laptop for school, budget $2000, details inside in ~tech

Comment on Trump revokes rule preventing White House staff from lobbying in ~news

Comment on Are software engineers "engineers"? in ~comp

Comment on The scary power of the companies that finally shut Trump up in ~tech

Comment on The scary power of the companies that finally shut Trump up in ~tech

Comment on The scary power of the companies that finally shut Trump up in ~tech

Comment on Donald Trump response to yesterday violent roitious insurrection at the Capitol in ~news

Comment on Day 8: Handheld Halting in ~comp

Comment on Day 8: Handheld Halting in ~comp

Comment on Day 7: Handy Haversacks in ~comp

Comment on Day 5: Binary Boarding in ~comp

Comment on <deleted topic> in ~comp

Comment on Day 4: Passport Processing in ~comp

Comment on Day 3: Toboggan Trajectory in ~comp

Comment on <deleted topic> in ~comp

Comment on <deleted topic> in ~comp