From c90ead0fea6ea97b8183bba2982c4bee2786f5bb Mon Sep 17 00:00:00 2001
From: Piotr Russ <piotr.russ@betvictor.com>
Date: Sun, 27 Dec 2020 12:39:09 +0100
Subject: day23

---
 day23/day23-2.js | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 day23/day23-2.js

(limited to 'day23/day23-2.js')

diff --git a/day23/day23-2.js b/day23/day23-2.js
new file mode 100644
index 0000000..536e3c3
--- /dev/null
+++ b/day23/day23-2.js
@@ -0,0 +1,57 @@
+const data = require('./data')
+const numbers = data.split('').map((n) => parseInt(n, 10))
+const min = Math.min(...numbers)
+const max = Math.max(...numbers)
+const start = numbers[0]
+const cupsLength = 1000000
+const cups = {}
+let current = numbers[0]
+
+numbers.forEach((n, i) => {
+  cups[n] = {
+    prev: numbers[(i + (numbers.length - 1)) % numbers.length],
+    next: numbers[(i + 1) % numbers.length],
+  }
+})
+
+for (let i = max + 1; i <= cupsLength; i++) {
+  cups[i] = {
+    prev: i - 1,
+    next: i + 1,
+  }
+}
+
+cups[start].prev = cupsLength
+cups[numbers[numbers.length - 1]].next = max + 1
+cups[max + 1].prev = numbers[numbers.length - 1]
+cups[cupsLength].next = start
+
+for (let i = 0; i < 10000000; i++) {
+  let destination = current - 1
+  const first = cups[current].next
+  const second = cups[first].next
+  const third = cups[second].next
+  const fourth = cups[third].next
+  cups[current].next = fourth
+
+  while (
+    destination < min
+    || destination === first
+    || destination === second
+    || destination === third
+  ) {
+    destination--
+    if (destination < min) { destination = cupsLength }
+  }
+
+  const afterDestination = cups[destination].next
+  cups[destination].next = first
+  cups[third].next = afterDestination
+  current = cups[current].next
+}
+
+const res1 = cups[1].next
+const res2 = cups[res1].next
+
+console.log('Answer: ', res1 * res2)
+
-- 
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