AoC 2020

aoc1.js

fetch("https://adventofcode.com/2020/day/1/input")
  .then(res => res.text())
  .then(text => text.split("\n").map(v => parseInt(v)))
  .then(values => {
   for(let i=0; i<values.length; i++) {
      const v1 = values[i]
      for(let j=i; j<values.length; j++) {
         const v2 = values[j]
         if( v1+v2 === 2020) {
             return v1*v2 
         }
      }
   }
}).then(console.log)

aoc10.js

const parse = (input, base) => 
  parseInt(base.split('').reduce((str, ch, index) => str.replaceAll(ch,index), input), base.length)

fetch("https://adventofcode.com/2020/day/5/input").then(res => res.text()).then(text => 
  text.split("\n")
    .map(line => parse(line.substr(0,7), "FB") * 8 + parse(line.substr(7),"LR"))
    .find((value, index, values) => !values.includes(value+1) && values.includes(value+2))
  + 1
).then(console.log)

aoc11.js

fetch("https://adventofcode.com/2020/day/6/input").then(res => res.text()).then(input => 
  input.split("\n\n").map(group => group.split("\n").reduce((responses, value) => value.split("").forEach((letter) => responses.add(letter)) || responses, new Set()).size).reduce((a,b) => a+b, 0)
).then(console.log)

AoC2.js

fetch("https://adventofcode.com/2020/day/1/input").then(res => res.text()).then(text => text.split("\n").map(v => parseInt(v))).then(values => {
   for(let i=0; i<values.length; i++) {
      const v1 = values[i]
      for(let j=i+1; j<values.length; j++) {
         const v2 = values[j]
         for(let l=j+1; l<values.length; l++) {
             const v3 = values[l]
             if( v1+v2+v3 === 2020) {
                return v1*v2*v3 
            }
         }

      }
   }
}).then(console.log)

aoc3.js

fetch("https://adventofcode.com/2020/day/2/input").then(res => res.text()).then(text => text.split("\n")).then(data => 
  data.filter(line => {
    try {
    const columns = line.split(" ")
    const range = columns.shift().split('-').map(v => parseInt(v))
    const letter = columns.shift().substr(0,1)
    const password = columns.join(" ")
    const n = password.split(letter).length-1
    console.log({line, n, range})
    return (n >= range[0]) && (n<= range[1])
    
    } catch(e) {
       console.error(`Error for line "${line}"`, e)
       return false
    }
}).length
).then(console.log)

aoc4.js

fetch("https://adventofcode.com/2020/day/2/input").then(res => res.text()).then(text => text.split("\n")).then(data => 
  data.filter(line => {
    try {
    const columns = line.split(" ")
    const range = columns.shift().split('-').map(v => parseInt(v))
    const letter = columns.shift().substr(0,1)
    const password = columns.join(" ")
    const hasLetterAt = range.map((i) => password.charAt(i-1) === letter)
    return (hasLetterAt[0] && !hasLetterAt[1]) || (hasLetterAt[1] && !hasLetterAt[0])
    
    } catch(e) {
       console.error(`Error for line "${line}"`, e)
       return false
    }
}).length
).then(console.log)

aoc5.js

fetch("https://adventofcode.com/2020/day/3/input").then(res => res.text()).then(text => text.split("\n")).then(lines => lines.map((line, index) => line.charAt(3*index % line.length) === '#').reduce((acc, tree) => acc + (tree ? 1 : 0), 0)).then(console.log)

aoc6.js

fetch("https://adventofcode.com/2020/day/3/input").then(res => res.text()).then(text => text.split("\n")).then(lines => 
  lines
  .map((line, index) => 
    [[1,1],[3,1],[5,1],[7,1],[1,2]]
      .map(([right,down]) => (index % down === 0) && line.charAt((right * (index / down)) % line.length) === '#')
  )    
  .reduce((acc, line) => line.map((tree, col) => (acc[col] || 0) + (tree?1:0)), [])
  .reduce((acc, v) => acc * v, 1)
)
  .then(console.log)

aoc7.js

fetch("https://adventofcode.com/2020/day/4/input").then(res => res.text()).then(input => 
  input.split("\n\n")
    .map(line => line.split(/[ \n]/).map(entry => entry.split(":"))
    .reduce(
      (missing,[key, value]) => value && missing.delete(key) && missing || missing, 
      new Set(["byr","iyr","eyr","hgt","hcl","ecl","pid"]))
    )
    .filter(missing => missing.size === 0)
    .length
).then(console.log)

aoc8.js

const isBetween = (min, max) => v => Math.max(min, Math.min(max, parseInt(v))) === parseInt(v)

const rules = {
  "byr": isBetween(1920, 2002),
  "iyr": isBetween(2010, 2020),
  "eyr": isBetween(2020, 2030),
  "hgt": v => {
    switch(v.substr(-2)) {
      case 'cm': return isBetween(150, 193)(v)
      case 'in': return isBetween(59, 76)(v)
    }
    return false
  },
  "hcl": v => /^#[0-9a-f]{6}$/.test(v),
  "ecl": v => ["amb","blu","brn","gry","grn","hzl","oth"].includes(v),
  "pid": v => /^[0-9]{9}$/.test(v)
}

fetch("https://adventofcode.com/2020/day/4/input").then(res => res.text()).then(input => 
  input.split("\n\n")
    .map(line => line.split(/[ \n]/)
      .map(entry => entry.split(":")
    )
    .reduce(
      (missing,[key, value]) => value && rules[key] && rules[key](value) && missing.delete(key) && missing || missing, 
      new Set(Object.keys(rules)))
    )
    .filter(missing => missing.size === 0)
    .length
  )
  .then(console.log)

aoc9.js

const parse = (input, base) => 
  parseInt(base.split('').reduce((str, ch, index) => str.replaceAll(ch,index), input), base.length)

fetch("https://adventofcode.com/2020/day/5/input").then(res => res.text()).then(text => 
  text.split("\n")
    .map(line => parse(line.substr(0,7), "FB") * 8 + parse(line.substr(7),"LR"))
    .reduce((current, id) => (id > current) ? id : current, 0)
).then(console.log)