Advent of Code 2022 - Day 8: Treetop Tree House Solution

Part 1

Let the code speak for itself

Implementation

1const fs = require("fs")
2
3const readData = () => {
4  const data = fs
5    .readFileSync("./input", "utf-8")
6    .split(/\r?\n/)
7    .map(row => row.split(""))
8
9  return data
10}
11
12const main = () => {
13  const matrix = readData()
14
15  const [numberOfRows, numberOfCols] = [matrix.length, matrix[0].length]
16
17  let res = 0
18
19  const isEdge = (row, col) =>
20    row === 0 ||
21    col === 0 ||
22    row === numberOfRows - 1 ||
23    col === numberOfCols - 1
24
25  const isVisible = (row, col) => {
26    if (isEdge(row, col)) return true
27
28    const isValid = cellValue => cellValue < matrix[row][col]
29
30    const [rowValues, colValues] = [
31      matrix[row],
32      Array.from({ length: numberOfRows }, (_, i) => matrix[i][col]),
33    ]
34
35    return [
36      rowValues.slice(0, col).every(isValid),
37      rowValues.slice(col + 1).every(isValid),
38      colValues.slice(0, row).every(isValid),
39      colValues.slice(row + 1).every(isValid),
40    ].some(Boolean)
41  }
42
43  for (let row = 0; row < numberOfRows; row++) {
44    for (let col = 0; col < numberOfCols; col++) {
45      res += isVisible(row, col)
46    }
47  }
48
49  console.log(res)
50}
51
52main()

Part 2

Early-break loop and count

Implementation

1const fs = require("fs")
2
3const readData = () => {
4  const data = fs
5    .readFileSync("./input", "utf-8")
6    .split(/\r?\n/)
7    .map(row => row.split(""))
8
9  return data
10}
11
12const main = () => {
13  const matrix = readData()
14
15  const [numberOfRows, numberOfCols] = [matrix.length, matrix[0].length]
16
17  let res = Number.NEGATIVE_INFINITY
18
19  const isEdge = (row, col) =>
20    row === 0 ||
21    col === 0 ||
22    row === numberOfRows - 1 ||
23    col === numberOfCols - 1
24
25  const calculateScenicScore = (row, col) => {
26    if (isEdge(row, col)) return 0
27
28    const scoreAccumulator = ({ count, stop }, el) => {
29      if (stop) return { count, stop }
30
31      stop = el >= matrix[row][col]
32      count += 1
33
34      return { count, stop }
35    }
36
37    const [rowValues, colValues] = [
38      matrix[row],
39      Array.from({ length: numberOfRows }, (_, i) => matrix[i][col]),
40    ]
41
42    return [
43      rowValues
44        .slice(0, col)
45        .reverse()
46        .reduce(scoreAccumulator, { count: 0, stop: false }).count,
47      rowValues
48        .slice(col + 1)
49        .reduce(scoreAccumulator, { count: 0, stop: false }).count,
50      colValues
51        .slice(0, row)
52        .reverse()
53        .reduce(scoreAccumulator, { count: 0, stop: false }).count,
54      colValues
55        .slice(row + 1)
56        .reduce(scoreAccumulator, { count: 0, stop: false }).count,
57    ].reduce((acc, el) => acc * el, 1)
58  }
59
60  for (let row = 0; row < numberOfRows; row++) {
61    for (let col = 0; col < numberOfCols; col++) {
62      res = Math.max(res, calculateScenicScore(row, col))
63    }
64  }
65
66  console.log(res)
67}
68
69main()

References

Original problem