day22

1 files changed, 40 insertions, 0 deletions

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)
+