Cleanup on 2024-08

2024/08/index.ts

@@ -1,26 +1,32 @@
 import { combinations, unique } from '../../utils/array.ts';
-import { inBounds, isCoordinateEqual } from '../../utils/coordinates.ts';
+import {
+  type Coordinates,
+  inBounds,
+  isCoordinateEqual
+} from '../../utils/coordinates.ts';
 
-export function solveFirst(input: string): number {
-  const rows = input.split('\n');
-
-  const antennas = new Map<string, [number, number][]>();
+export function groupCoordinates(rows: string[]) {
+  const antennas = new Map<string, Coordinates>();
 
   for (let y = 0; y < rows.length; y++) {
     for (let x = 0; x < rows[y].length; x++) {
-      const digit = rows[y][x];
-      if (digit === '.') {
+      const char = rows[y][x];
+      if (char === '.') {
         continue;
       }
-      const entry = antennas.get(digit) || [];
+      const entry = antennas.get(char) || [];
       entry.push([x, y]);
-      antennas.set(digit, entry);
+      antennas.set(char, entry);
     }
   }
-  const antiNodes: [number, number][] = [];
+  return antennas;
+}
+
+export function solveFirst(input: string): number {
+  const rows = input.split('\n');
+  const antennas = groupCoordinates(rows);
+  const antiNodes: Coordinates = [];
 
-  // console.log(rows);
-  // console.log(antennas);
   antennas.forEach((positions) => {
     combinations(positions).forEach(({ a, b }) =>
       antiNodes.push([a[0] - (b[0] - a[0]), a[1] - (b[1] - a[1])])
@@ -31,36 +37,18 @@ export function solveFirst(input: string): number {
     .filter(inBounds(rows[0].length, rows.length))
     .filter(unique(isCoordinateEqual));
 
-  // validAntiNodes.forEach(([x, y]) => rows[y][x] === '.' && replaceChar(rows, x, y, '#'));
-  //
-  // console.log(rows.join('\n'));
   return validAntiNodes.length;
 }
 
 export function solveSecond(input: string): number {
   const rows = input.split('\n');
 
-  const antennas = new Map<string, [number, number][]>();
-
-  const yMax = rows.length;
-  const xMax = rows[0].length;
-
-  for (let y = 0; y < yMax; y++) {
-    for (let x = 0; x < xMax; x++) {
-      const digit = rows[y][x];
-      if (digit === '.') {
-        continue;
-      }
-      const entry = antennas.get(digit) || [];
-      entry.push([x, y]);
-      antennas.set(digit, entry);
-    }
-  }
-  const antiNodes: [number, number][] = [];
+  const antennas = groupCoordinates(rows);
+  const antiNodes: Coordinates = [];
 
   antennas.forEach((positions) => {
     combinations(positions).forEach(({ a, b }) => {
-      for (let y = 0; y < yMax; y++) {
+      for (let y = 0; y < rows.length; y++) {
         antiNodes.push([a[0] + (b[0] - a[0]) * y, a[1] + (b[1] - a[1]) * y]);
       }
     });
@@ -70,7 +58,8 @@ export function solveSecond(input: string): number {
     .filter(inBounds(rows[0].length, rows.length))
     .filter(unique(isCoordinateEqual));
 
-  // console.log(validAntiNodes);
+  // Show the anti-nodes on the input map
+  //
   // validAntiNodes.forEach(
   //   ([x, y]) => rows[y][x] === '.' && replaceChar(rows, x, y, '#')
   // );