day-8.ts

import { returnLinebreakRegex } from "./regex.ts";

export async function dayEightA(): Promise<number> {
  let numberOfAntinodes: number = 0;
  const linebreak: RegExp = returnLinebreakRegex();
  const text: string = await Deno.readTextFile("day-8.input");
  const rows: string[] = text.split(linebreak);
  const towerMap: string[][] = rows.map((row: string): string[] =>
    row.split("")
  );
  const antinodeMap: string[][] = rows.map((row: string): string[] =>
    row.split("")
  );
  for (let i = 0; i < towerMap.length; i++) {
    for (let j = 0; j < towerMap[0].length; j++) {
      if (towerMap[i][j] === ".") {
        continue;
      }
      getAntinodes(towerMap, i, j).forEach((coordinates: number[]): void => {
        antinodeMap[coordinates[0]][coordinates[1]] = "#";
      });
    }
  }
  antinodeMap.forEach((row: string[]): void => {
    numberOfAntinodes += row.filter((z: string): boolean => z === "#").length;
  });
  return numberOfAntinodes;
}

export async function dayEightB(): Promise<number> {
  let numberOfAntinodes: number = 0;
  const linebreak: RegExp = returnLinebreakRegex();
  const text: string = await Deno.readTextFile("day-8.input");
  const rows: string[] = text.split(linebreak);
  const towerMap: string[][] = rows.map((row: string): string[] =>
    row.split("")
  );
  const antinodeMap: string[][] = rows.map((row: string): string[] =>
    row.split("")
  );
  for (let i = 0; i < towerMap.length; i++) {
    for (let j = 0; j < towerMap[0].length; j++) {
      if (towerMap[i][j] === ".") {
        continue;
      }
      getAntinodesB(towerMap, i, j).forEach((coordinates: number[]): void => {
        antinodeMap[coordinates[0]][coordinates[1]] = "#";
      });
    }
  }
  antinodeMap.forEach((row: string[]): void => {
    numberOfAntinodes += row.filter((z: string): boolean => z === "#").length;
  });
  return numberOfAntinodes;
}

function getAntinodes(map: string[][], i: number, j: number): number[][] {
  const antinodeCoordinates: number[][] = [];
  let xDistance: number = 0;
  let yDistance: number = 0;
  for (let x = 0; x < map.length; x++) {
    for (let y = 0; y < map[0].length; y++) {
      if (map[x][y] === map[i][j] && (x !== i || y !== j)) {
        xDistance = x - i;
        yDistance = y - j;
        if (isInBound(map, x + xDistance, y + yDistance)) {
          if (
            !antinodeCoordinates.includes([x + xDistance, y + yDistance]) &&
            !(x + xDistance === i && y + yDistance === j)
          ) {
            antinodeCoordinates.push([x + xDistance, y + yDistance]);
          }
        }
      }
    }
  }
  return antinodeCoordinates;
}

function getAntinodesB(map: string[][], i: number, j: number): number[][] {
  const antinodeCoordinates: number[][] = [];
  let xDistance: number = 0;
  let yDistance: number = 0;
  for (let x = 0; x < map.length; x++) {
    for (let y = 0; y < map[0].length; y++) {
      if (map[x][y] === map[i][j] && (x !== i || y !== j)) {
        if (!antinodeCoordinates.includes([x, y])) {
          antinodeCoordinates.push([x, y]);
        }
        xDistance = x - i;
        yDistance = y - j;
        while (isInBound(map, x + xDistance, y + yDistance)) {
          if (!antinodeCoordinates.includes([x + xDistance, y + xDistance])) {
            antinodeCoordinates.push([x + xDistance, y + yDistance]);
          }
          xDistance = xDistance + x - i;
          yDistance = yDistance + y - j;
        }
      }
    }
  }
  return antinodeCoordinates;
}

function isInBound(map: string[][], x: number, y: number): boolean {
  return (x < map.length && x >= 0 && y < map[0].length && y >= 0);
}

if (import.meta.main) {
  console.log("Part 1:", await dayEightA());
  console.log("Part 2:", await dayEightB());
}