advent of code day 4

aoc_day04.ts

const input = await Deno.readTextFile("input.txt");

const directions = [
  [0, 1],
  [0, -1],
  [1, 0],
  [1, 1],
  [1, -1],
  [-1, 0],
  [-1, -1],
  [-1, 1],
];

const grid = input.split("\n").map((row) => row.split(""));
const xmas = "XMAS";

let total_1 = 0;

for (let row = 0; row < grid.length; row++) {
  for (let col = 0; col < grid[row].length; col++) {
    for (const dir of directions) {
      for (let w = 0; w < xmas.length; w++) {
        const r = row + dir[0] * w;
        const c = col + dir[1] * w;

        if (r < 0 || r >= grid.length || c < 0 || c >= grid[r].length) {
          break;
        }

        if (grid[r][c] !== xmas[w]) {
          break;
        }

        if (w === xmas.length - 1) {
          total_1++;
        }
      }
    }
  }
}

let total_2 = 0;

for (let row = 0; row < grid.length; row++) {
  for (let col = 0; col < grid[row].length; col++) {
    if (grid[row][col] === "A") {
      try {
        const lr = [grid[row - 1][col - 1], grid[row + 1][col + 1]];
        const rl = [grid[row - 1][col + 1], grid[row + 1][col - 1]];

        if (
          lr.includes("M") &&
          lr.includes("S") &&
          rl.includes("M") &&
          rl.includes("S")
        ) {
          total_2++;
        }
      } catch {
        break;
      }
    }
  }
}

console.log({ total_1, total_2 });