From f3273983a827b01a12f1ddf6215f8d69938821eb Mon Sep 17 00:00:00 2001
From: Piotr Russ <mail@pruss.it>
Date: Fri, 25 Dec 2020 01:02:32 +0100
Subject: day22

---
 day22/data.js    | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 day22/day22-1.js | 21 +++++++++++++++++++++
 day22/day22-2.js | 40 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+)
 create mode 100644 day22/data.js
 create mode 100644 day22/day22-1.js
 create mode 100644 day22/day22-2.js

(limited to 'day22')

diff --git a/day22/data.js b/day22/data.js
new file mode 100644
index 0000000..e85ae4e
--- /dev/null
+++ b/day22/data.js
@@ -0,0 +1,57 @@
+const data = `
+Player 1:
+47
+19
+22
+31
+24
+6
+10
+5
+1
+48
+46
+27
+8
+45
+16
+28
+33
+41
+42
+36
+50
+39
+30
+11
+17
+
+Player 2:
+4
+18
+21
+37
+34
+15
+35
+38
+20
+23
+9
+25
+32
+13
+26
+2
+12
+44
+14
+49
+3
+40
+7
+43
+29
+`
+
+module.exports = data
diff --git a/day22/day22-1.js b/day22/day22-1.js
new file mode 100644
index 0000000..f2528f5
--- /dev/null
+++ b/day22/day22-1.js
@@ -0,0 +1,21 @@
+const data = require('./data')
+const [player1, player2] = data.split('\n\n').filter(Boolean)
+  .map(p => p.split(/\n/g).filter(Boolean).slice(1))
+
+const round = () => {
+  const c1 = player1.shift()
+  const c2 = player2.shift()
+  if (parseInt(c1) > parseInt(c2)) {
+    player1.push(c1, c2)
+  } else {
+    player2.push(c2, c1)
+  }
+}
+
+while (player1.length>0 && player2.length>0) { round() }
+
+const cards = player1.length > 0 ? player1 : player2
+const score = cards.reverse().map((c, i) => parseInt(c) * (i+1)).reduce((a,b) => a + b, 0)
+
+console.log('Answer: ', score)
+
diff --git a/day22/day22-2.js b/day22/day22-2.js
new file mode 100644
index 0000000..e79d8e7
--- /dev/null
+++ b/day22/day22-2.js
@@ -0,0 +1,40 @@
+const data = require('./data')
+const [player1, player2] = data
+  .split('\n\n').filter(Boolean)
+  .map(p => p.split(/\n/g).filter(Boolean).slice(1).map(n => parseInt(n)))
+
+const game = (players, rec = false) => {
+  const prev = {}
+  const p1 = players[0]
+  const p2 = players[1]
+
+  while (players.every((player) => player.length > 0)) {
+    const k = players.map(p => p.join(',')).join('|')
+    if (prev[k]) { return [[1], []] }
+    prev[k] = true
+
+    const c1 = p1.shift()
+    const c2 = p2.shift()
+
+    if (rec && p1.length >= c1 && p2.length >= c2) {
+      const [r1, r2] = game([[...p1.slice(0, c1)], [...p2.slice(0, c2)]], true)
+      if (r1.length > r2.length) {
+        p1.push(c1, c2)
+      } else {
+        p2.push(c2, c1)
+      }
+    } else if (c1 > c2) {
+      p1.push(c1, c2)
+    } else {
+      p2.push(c2, c1)
+    }
+  }
+
+  return players
+}
+
+const score = game([player1, player2], true).flat().reverse()
+  .map((c, i) => parseInt(c) * (i+1)).reduce((a,b) => a+b, 0)
+
+console.log('Answer: ', score)
+
-- 
cgit v1.2.3