Advent of Code 2023 Day One

I’ll just say up front that I never finish the whole Advent of Code. I’m usually good for a few weeks and then they get really hard and life gets busy because of the holidays. So, with my excuses out of the way here is my solution to Day 1 of the Advent of Code.

Part One

const testInput = `1abc2
pqr3stu8vwx
a1b2c3d4e5f
treb7uchet`;

const numberWords = {
  one: 1,
  two: 2,
  three: 3,
  four: 4,
  five: 5,
  six: 6,
  seven: 7,
  eight: 8,
  nine: 9,
};

const extractNumbers = input => {
  const allMatches =
    input.match(/[1-9]|one|two|three|four|five|six|seven|eight|nine/gi) || [];
  return allMatches.map(match =>
    isNaN(match) ? numberWords[match.toLowerCase()] : Number(match)
  );
};

const concatFirstAndLastNumber = arr => {
  return Number(`${arr[0]}${arr[arr.length - 1]}`);
};

const total = input => {
  return input
    .split("\n")
    .map(extractNumbers)
    .map(concatFirstAndLastNumber)
    .reduce((acc, curr) => acc + curr, 0);
};

console.log(total(testInput)); // 142

Part 2

const testInput = `two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen
sdoneight37`;

const numberWords = {
  one: 1,
  two: 2,
  three: 3,
  four: 4,
  five: 5,
  six: 6,
  seven: 7,
  eight: 8,
  nine: 9,
  oneight: 18,
  twone: 21,
  threeight: 38,
  fiveight: 58,
  sevenine: 79,
  eightwo: 82,
  eighthree: 83,
  nineight: 98,
};

const extractNumbers = input => {
  const allMatches =
    input.match(/[1-9]|one|two|three|four|five|six|seven|eight|nine/gi) || [];
  return allMatches.map(match =>
    isNaN(match) ? numberWords[match.toLowerCase()] : Number(match)
  );
};

const concatFirstAndLastNumber = arr => {
  return Number(`${arr[0]}${arr[arr.length - 1]}`);
};

const solve = input => {
  input = input.replace(
    /oneight|twone|threeight|fiveight|sevenine|eightwo|eighthree|nineight/gi,
    matched => numberWords[matched]
  );
  return input
    .split("\n")
    .map(extractNumbers)
    .map(concatFirstAndLastNumber)
    .reduce((acc, curr) => acc + curr, 0);
};

console.log(solve(testInput)); // 298

I slightly altered the puzzles given input to take into account a case where the spelled numbers could possibly run together. This tripped me up on my first attempt because I didn’t think about cases like oneight, fiveight, nineight, etc.