From 987a2acba514a732efabcf0b4b8baa41fece434c Mon Sep 17 00:00:00 2001
From: Shahar Talmi <shahar@wix.com>
Date: Sat, 16 Dec 2023 09:39:13 +0200
Subject: [PATCH] refactor

---
 src/2023/day16.js | 59 +++++++++++++++++++++++++----------------------
 1 file changed, 31 insertions(+), 28 deletions(-)

diff --git a/src/2023/day16.js b/src/2023/day16.js
index d0a2305b..ce555adf 100644
--- a/src/2023/day16.js
+++ b/src/2023/day16.js
@@ -1,38 +1,42 @@
+function getNextSteps(map, x, y, d) {
+  const RIGHT = { x: x + 1, y: y, d: 'right' };
+  const LEFT = { x: x - 1, y: y, d: 'left' };
+  const UP = { x: x, y: y - 1, d: 'up' };
+  const DOWN = { x: x, y: y + 1, d: 'down' };
+
+  if (map[y][x].c === '-' && (d === 'up' || d === 'down')) {
+    return [LEFT, RIGHT];
+  } else if (map[y][x].c === '|' && (d === 'right' || d === 'left')) {
+    return [UP, DOWN];
+  } else if (map[y][x].c === '\\') {
+    if (d === 'right') return [DOWN];
+    if (d === 'left') return [UP];
+    if (d === 'up') return [LEFT];
+    if (d === 'down') return [RIGHT];
+  } else if (map[y][x].c === '/') {
+    if (d === 'right') return [UP];
+    if (d === 'left') return [DOWN];
+    if (d === 'up') return [RIGHT];
+    if (d === 'down') return [LEFT];
+  } else {
+    if (d === 'right') return [RIGHT];
+    if (d === 'left') return [LEFT];
+    if (d === 'up') return [UP];
+    if (d === 'down') return [DOWN];
+  }
+}
+
 export function part1(input, start = { x: 0, y: 0, d: 'right' }) {
   const map = input
     .split('\n')
     .map(line => line.split('').map(c => ({ c, l: [] })));
   const queue = [start];
   while (queue.length > 0) {
-    let next = [];
     const { x, y, d } = queue.shift();
-    const RIGHT = { x: x + 1, y: y, d: 'right' };
-    const LEFT = { x: x - 1, y: y, d: 'left' };
-    const UP = { x: x, y: y - 1, d: 'up' };
-    const DOWN = { x: x, y: y + 1, d: 'down' };
-
+    const next = getNextSteps(map, x, y, d).filter(
+      ({ x, y, d }) => map[y]?.[x]?.l.includes(d) === false,
+    );
     map[y][x].l.push(d);
-    if (map[y][x].c === '-' && (d === 'up' || d === 'down')) {
-      next.push(LEFT, RIGHT);
-    } else if (map[y][x].c === '|' && (d === 'right' || d === 'left')) {
-      next.push(UP, DOWN);
-    } else if (map[y][x].c === '\\') {
-      if (d === 'right') next.push(DOWN);
-      if (d === 'left') next.push(UP);
-      if (d === 'up') next.push(LEFT);
-      if (d === 'down') next.push(RIGHT);
-    } else if (map[y][x].c === '/') {
-      if (d === 'right') next.push(UP);
-      if (d === 'left') next.push(DOWN);
-      if (d === 'up') next.push(RIGHT);
-      if (d === 'down') next.push(LEFT);
-    } else {
-      if (d === 'right') next.push(RIGHT);
-      if (d === 'left') next.push(LEFT);
-      if (d === 'up') next.push(UP);
-      if (d === 'down') next.push(DOWN);
-    }
-    next = next.filter(({ x, y, d }) => map[y]?.[x]?.l.includes(d) === false);
     queue.push(...next);
   }
   return map.flatMap(lines => lines.filter(c => c.l.length > 0)).length;
@@ -53,6 +57,5 @@ export function part2(input) {
   for (let y = 0; y < map.length; y++) {
     max = Math.max(max, part1(input, { x: map[0].length - 1, y, d: 'left' }));
   }
-
   return max;
 }