aoc24/solutions/02.ts

import { solvables } from "../main.ts";

import type { Solvable } from "../solvable.ts";
import { readInput } from "../utils.ts";

class DayTwo implements Solvable {
    input = readInput('02')

    public part1(): DayTwo {
        const reports = this.input.trim().split("\n").map(line => line.split(' ').map(level => Number.parseInt(level)))
        const slidingWindow = (levels: number[]): boolean => { 
            const gradients: ("ascending" | "descending")[] = []
            let [i,j] = [0,1]
            while (j < levels.length) {
                // is unsafe if ascent / descend bigger than 3 or smaller than 1
                const diff = Math.abs(levels[i] - levels[j])
                if (diff > 3 || diff < 1) {
                    return false
                }
                // calculate positive or negative gradient
                if (levels[i] < levels[j]) {
                    gradients.push("ascending") 
                } else if (levels[i] > levels[j]) {
                    gradients.push("descending")
                }                i++
                j++
            }
            // is safe and constant gradient?
            const constantGradient = gradients.every((gradient) => gradient === "ascending") || gradients.every((gradient) => gradient === "descending")
            return constantGradient
        }
        const result = reports.map(levels => slidingWindow(levels)).filter(level_safe => level_safe === true).length
        console.log(result)

        return this
    }
    public part2(): DayTwo {
        return this
    }
}

solvables.push(new DayTwo())