advent of code day 2

aoc_day02.ts

const input = await Deno.readTextFile("input.txt");
const data = input.split("\n");

const isSafe = (levels: number[]): boolean => {
  const diffs = levels.slice(1).map((num, idx) => num - levels[idx]);

  // Stupid off by one error >:(
  if (diffs.length === 0) {
    return false;
  }

  const increasing = diffs.every((diff) => diff >= 1 && diff <= 3);
  const decreasing = diffs.every((diff) => diff <= -1 && diff >= -3);

  return increasing || decreasing;
};

const canBeSafeWithOneRemoval = (levels: number[]): boolean => {
  for (let i = 0; i < levels.length; i++) {
    const modifiedLevels = levels.slice(0, i).concat(levels.slice(i + 1));
    if (isSafe(modifiedLevels)) {
      return true;
    }
  }
  return false;
};

let safeCount = 0;
let safeIfOneRemovedCount = 0;

data.forEach((row) => {
  const levels = row.split(" ").map((num) => Number(num.trim()));

  if (isSafe(levels)) {
    safeCount++;
  }

  if (isSafe(levels) || canBeSafeWithOneRemoval(levels)) {
    safeIfOneRemovedCount++;
  }
});

console.log({ safeCount, safeIfOneRemovedCount });