aoc-2024/day2.ts

import fs from "node:fs";

const input = fs.readFileSync("inputs/day2").toString();

const rows = input.split("\n").filter(Boolean);

function safe_levels(_row: number[]) {
    const row = [..._row];
    while (row.length > 1) {
        const diff = row[1] - row[0];
        if (diff > 3 || diff < 1) return false;
        row.shift();
    }
    return true;
}

function puzzle1() {
    return rows.map((row) => row.split(/\s+/g).map(i => +i))
    .filter(row => safe_levels(row) || safe_levels(row.toReversed())).length;
}

console.log("Puzzle 1", puzzle1());

function dampen_lists(row: number[]) {
    const rows: number[][] = new Array(row.length).fill(row).map((_row, i) => {
        const row = [..._row];
        row.splice(i, 1);
        return row;
    });
    return [row, ...rows].filter(safe_levels).length > 0;
}

function puzzle2() {
    return rows.map((row) => row.split(/\s+/g).map(i => +i))
    .filter(row => dampen_lists(row) || dampen_lists(row.toReversed())).length;
}

console.log("Puzzle 2", puzzle2());