Advent of Code Day 4

part1.js

const { readFile } = require("fs/promises");
async function readRawInput() {
  const path = "./input.txt";
  const content = await readFile(path, { encoding: "utf-8" });
  return content;
}

function parseLine(line) {
  const pairs = line.split(",");
  const firstPair = parseRangeString(pairs[0]);
  const secondPair = parseRangeString(pairs[1]);
  return isFullyContained(firstPair, secondPair);
}

function parseRangeString(rangeString) {
  const pair = rangeString.split("-");
  const firstNumber = Number(pair[0]);
  const secondNumber = Number(pair[1]);

  return [firstNumber, secondNumber];
}

function isFullyContained(firstPair, secondPair) {
  if (firstPair[0] <= secondPair[0] && firstPair[1] >= secondPair[1]) {
    return true;
  }
  if (firstPair[0] >= secondPair[0] && firstPair[1] <= secondPair[1]) {
    return true;
  }
  return false;
}

async function main() {
  const raw = await readRawInput();
  const lines = raw.split("\n");

  const numberOfFullyContainingAssignments = lines
    .map(parseLine)
    .reduce((a, b) => a + (b ? 1 : 0), 0);

  console.log(numberOfFullyContainingAssignments);
}

main();

part2.js

const { readFile } = require("fs/promises");
async function readRawInput() {
  const path = "./input.txt";
  const content = await readFile(path, { encoding: "utf-8" });
  return content;
}

function parseLine(line) {
  const pairs = line.split(",");
  const firstPair = parseRangeString(pairs[0]);
  const secondPair = parseRangeString(pairs[1]);
  return isOverlapped(firstPair, secondPair);
}

function parseRangeString(rangeString) {
  const pair = rangeString.split("-");
  const firstNumber = Number(pair[0]);
  const secondNumber = Number(pair[1]);

  return [firstNumber, secondNumber];
}

function isOverlapped(firstPair, secondPair) {
  if (firstPair[1] >= secondPair[0] && firstPair[0] <= secondPair[0]) {
    return true;
  }
  if (secondPair[1] >= firstPair[0] && secondPair[0] <= firstPair[0]) {
    return true;
  }
  return false;
}

async function main() {
  const raw = await readRawInput();
  const lines = raw.split("\n");

  const numberOfOverlappingAssignments = lines
    .map(parseLine)
    .reduce((a, b) => a + (b ? 1 : 0), 0);

  console.log(numberOfOverlappingAssignments);
}

main();