day20

1 files changed, 40 insertions, 0 deletions

diff --git a/day20/day20-1.js b/day20/day20-1.js
new file mode 100644
index 0000000..865410d
--- /dev/null
+++ b/day20/day20-1.js
@@ -0,0 +1,40 @@
+const data = require('./data')
+const tiles = []
+const getSides = (t) => {
+  const sides = [t[0], t.map(r=>r[r.length-1]).join(''), t[t.length-1], t.map(r=>r[0]).join('')]
+  const reversed = sides.map(s => s.split("").reverse().join(""))
+  return [...sides, ...reversed]
+}
+
+data
+  .split('\n\n')
+  .map(s => s.split('\n').filter(Boolean))
+  .forEach(s => tiles.push({
+    id: parseInt(s[0].match(/[0-9]+/g)[0]),
+    array: s.slice(1),
+    sides: getSides(s.slice(1)),
+    matches: []
+  }))
+
+const check = (t1, t2) => {
+  for (const s1 of t1.sides) for (const s2 of t2.sides) {
+    if (s1 === s2) {return s1}
+  }
+  return null
+}
+
+for (let i=0; i< tiles.length; i++) for (let j=i+1; j<tiles.length; j++) {
+  const match = check(tiles[i], tiles[j])
+  if (match) {
+    tiles[i].matches.push({ id: tiles[j].id, side: match })
+    tiles[j].matches.push({ id: tiles[i].id, side: match })
+  }
+}
+
+const res = tiles
+  .filter(t => t.matches.length === 2)
+  .map(t => t.id)
+  .reduce((a, b) => a * b, 1)
+
+console.log('Answer: ', res)
+