day 08

part1.ts

const file = Deno.readTextFileSync('days/06/input.txt')
const map = file.split('\n').map(line => line.split('').map(char => parseInt(char)))
const cols = map[0].length
const rows = map.length

const visible = new Set<string>()

// top to bottom
for (let x = 0; x < cols; x++) {
    let prev = -1
    for (let y = 0; y < rows; y++) {
        let num = map[y][x]
        if (num == prev || num <= prev) {
            continue
        }
        visible.add(`${y}x${x}`)
        prev = num
    }
}

// bottom to top
for (let x = 0; x < cols; x++) {
    let prev = -1
    for (let y = rows - 1; y >= 0; y--) {
        let num = map[y][x]
        if (num == prev || num <= prev) {
            continue
        }
        visible.add(`${y}x${x}`)
        prev = num
    }
}

// left to right
for (let y = 0; y < rows; y++) {
    let prev = -1
    for (let x = 0; x < cols; x++) {
        let num = map[y][x]
        if (num == prev || num <= prev) {
            continue
        }
        visible.add(`${y}x${x}`)
        prev = num
    }
}

// right to left
for (let y = 0; y < rows; y++) {
    let prev = -1
    for (let x = cols - 1; x >= 0; x--) {
        let num = map[y][x]
        if (num == prev || num <= prev) {
            continue
        }
        visible.add(`${y}x${x}`)
        prev = num
    }
}

console.log(visible.size)

part2.ts

const file = Deno.readTextFileSync('days/06/input.txt')
const map = file.split('\n').map(line => line.split('').map(char => parseInt(char)))
const cols = map[0].length
const rows = map.length

function calculateScore(x: number, y: number) {
    let totalScore = 1;
    let val = map[y][x];

    function* slope(mx: number, my: number) {
        for (let px = x + mx, py = y + my; px >= 0 && py >= 0 && px < cols && py < rows; px += mx, py += my) {
            yield map[py][px]
        }
    }

    function findTrees(mx: number, my: number) {
        let score = 0;
        for (const num of slope(mx, my)) {
            score += 1
            if (num >= val) {
                break
            }
        }
        totalScore *= score
    }

    findTrees(1, 0)
    findTrees(0, 1)
    findTrees(-1, 0)
    findTrees(0, -1)

    return totalScore
}

let highestScore = 0
for (let x = 1; x < cols - 1; x++) {
    for (let y = 1; y < rows - 1; y++) {
        let score = calculateScore(x, y)
        if (score > highestScore) {
            highestScore = score
        }
    }
}

console.log(highestScore)