day 8

src/day08/README.md

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+# 🎄 Advent of Code 2021 - day 8 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2021/day/8)
+
+## Notes
+
+...

src/day08/index.js

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+import run from "aocrunner"
+
+const parseInput = (rawInput) =>
+  rawInput
+    .split("\n")
+    .map((x) =>
+      x
+        .split(" | ")
+        .map((x) => x.split(" ").map((x) => [...x].sort().join(""))),
+    )
+
+const part1 = (rawInput) => {
+  const input = parseInput(rawInput)
+  return input.reduce(
+    (acc, [samples, outputs]) =>
+      acc + outputs.filter((x) => [2, 4, 3, 7].includes(x.length)).length,
+    0,
+  )
+}
+
+const part2 = (rawInput) => {
+  function frequencies(str) {
+    return str.split("").reduce((total, letter) => {
+      total[letter] ? total[letter]++ : (total[letter] = 1)
+      return total
+    }, {})
+  }
+  const input = parseInput(rawInput)
+  return input.reduce((acc, [samples, outputs]) => {
+    const freq = Object.entries(frequencies(samples.join("")))
+    const segments = Array(7)
+    segments[4] = freq.find((x) => x[1] == 4)[0]
+    const one = samples.find((x) => x.length == 2)
+    const four = samples.find((x) => x.length == 4)
+    const seven = samples.find((x) => x.length == 3)
+    const eight = samples.find((x) => x.length == 7)
+    segments[0] = [...seven].filter((x) => one.indexOf(x) < 0)[0]
+    const two = samples.find(
+      (x) => x.length == 5 && x.indexOf(segments[4]) >= 0,
+    )
+    segments[2] = freq.find((x) => x[1] == 8 && x[0] != segments[0])[0]
+    const five = samples.find(
+      (x) => x.length == 5 && x.indexOf(segments[2]) < 0,
+    )
+    const three = samples.find((x) => x.length == 5 && x != two && x != five)
+    const six = samples.find((x) => x.length == 6 && x.indexOf(segments[2]) < 0)
+    const nine = samples.find(
+      (x) => x.length == 6 && x.indexOf(segments[4]) < 0,
+    )
+    const zero = samples.find((x) => x.length == 6 && x != six && x != nine)
+
+    const key = [zero, one, two, three, four, five, six, seven, eight, nine]
+    return (
+      acc +
+      parseInt(
+        outputs.reduce((acc, digit) => acc + key.indexOf(digit), ""),
+        10,
+      )
+    )
+  }, 0)
+}
+
+run({
+  part1: {
+    tests: [
+      {
+        input: `be cfbegad cbdgef fgaecd cgeb fdcge agebfd fecdb fabcd edb | fdgacbe cefdb cefbgd gcbe
+edbfga begcd cbg gc gcadebf fbgde acbgfd abcde gfcbed gfec | fcgedb cgb dgebacf gc
+fgaebd cg bdaec gdafb agbcfd gdcbef bgcad gfac gcb cdgabef | cg cg fdcagb cbg
+fbegcd cbd adcefb dageb afcb bc aefdc ecdab fgdeca fcdbega | efabcd cedba gadfec cb
+aecbfdg fbg gf bafeg dbefa fcge gcbea fcaegb dgceab fcbdga | gecf egdcabf bgf bfgea
+fgeab ca afcebg bdacfeg cfaedg gcfdb baec bfadeg bafgc acf | gebdcfa ecba ca fadegcb
+dbcfg fgd bdegcaf fgec aegbdf ecdfab fbedc dacgb gdcebf gf | cefg dcbef fcge gbcadfe
+bdfegc cbegaf gecbf dfcage bdacg ed bedf ced adcbefg gebcd | ed bcgafe cdgba cbgef
+egadfb cdbfeg cegd fecab cgb gbdefca cg fgcdab egfdb bfceg | gbdfcae bgc cg cgb
+gcafb gcf dcaebfg ecagb gf abcdeg gaef cafbge fdbac fegbdc | fgae cfgab fg bagce`,
+        expected: 26,
+      },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      {
+        input: `be cfbegad cbdgef fgaecd cgeb fdcge agebfd fecdb fabcd edb | fdgacbe cefdb cefbgd gcbe
+edbfga begcd cbg gc gcadebf fbgde acbgfd abcde gfcbed gfec | fcgedb cgb dgebacf gc
+fgaebd cg bdaec gdafb agbcfd gdcbef bgcad gfac gcb cdgabef | cg cg fdcagb cbg
+fbegcd cbd adcefb dageb afcb bc aefdc ecdab fgdeca fcdbega | efabcd cedba gadfec cb
+aecbfdg fbg gf bafeg dbefa fcge gcbea fcaegb dgceab fcbdga | gecf egdcabf bgf bfgea
+fgeab ca afcebg bdacfeg cfaedg gcfdb baec bfadeg bafgc acf | gebdcfa ecba ca fadegcb
+dbcfg fgd bdegcaf fgec aegbdf ecdfab fbedc dacgb gdcebf gf | cefg dcbef fcge gbcadfe
+bdfegc cbegaf gecbf dfcage bdacg ed bedf ced adcbefg gebcd | ed bcgafe cdgba cbgef
+egadfb cdbfeg cegd fecab cgb gbdefca cg fgcdab egfdb bfceg | gbdfcae bgc cg cgb
+gcafb gcf dcaebfg ecagb gf abcdeg gaef cafbge fdbac fegbdc | fgae cfgab fg bagce`,
+        expected: 61229,
+      },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+})
+
+/*
+number of segments
+0: 6
+1: 2
+2: 5
+3: 5
+4: 4
+5: 5
+6: 6
+7: 3
+8: 7
+9: 6
+
+segment # usage count
+0: 8
+1: 6
+2: 8
+3: 7
+4: 4
+5: 9
+6: 7
+*/