aoc24/solutions/04-a.ts

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

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

class DayFour implements Solvable {
    input = readInput('04')

    public part1(): Solvable {

        const transpose = (m: string[][]) => m[0].map((_, i) => m.map(x => x[i]))

        const matrix = this.input.split('\n').map(line => line.split(''))

        const countOccHorizontal = (mat: string[][]) => mat
            .map(line => line.join('')
                .matchAll(/(XMAS|SAMX)/g)
                .map(match => match[0])
                .toArray().length)
            .reduce((prev, curr) => prev + curr)

        // b/y = height
        // a/x = width
        // start top right

        const getDiagonals = (mat: string[][]) => {
            let [b, a] = [0, 140 - 1]
            const lines = []
            while (b < mat.length) {
                let line = ''
                for (let [y, x] = [b, a]; x < 140 && y < 140; y++, x++)
                    line += mat[y][x]

                lines.push(line.split(''))

                if (a > 0) {
                    a--
                } else {
                    b++
                }
            }
            return lines
        }

        // console.log(getDiagonals(matrix.reverse()))

        console.log(transpose(matrix).map(line => line.join('')))

        const downRight = countOccHorizontal(getDiagonals(matrix))
        const downLeft = countOccHorizontal(getDiagonals(matrix.reverse()))
        const horizontal = countOccHorizontal(matrix)
        const vertical = countOccHorizontal(transpose(matrix))

        console.log(horizontal + vertical + downRight + downLeft)

        return this
    }

    public part2(): Solvable {
        return this
    }
}

solvables.push(new DayFour())