2023 Day 7 Part 2

2023/day07.nim

@@ -36,6 +36,14 @@ func parseHand(text: string): Hand =
 func parseHands(text: string): seq[Hand] =
   text.strip.splitLines.map(parseHand)
 
+const five = 7
+const four = 6
+const full = 5
+const three = 4
+const twoPair = 3
+const pair = 2
+const high = 1
+
 func strength(hand: Hand): int =
   let count = newCountTable(hand.cards)
 
@@ -44,19 +52,19 @@ func strength(hand: Hand): int =
     counts.inc v
 
   if counts[5] > 0:
-    return 7
+    return five
   if counts[4] > 0:
-    return 6
+    return four
   if counts[3] > 0:
     if counts[2] > 0:
-      return 5
+      return full
     else:
-      return 4
+      return three
   if counts[2] == 2:
-    return 3
+    return twoPair
   if counts[2] == 1:
-    return 2
+    return pair
-  return 1
+  return high
 
 func cmpHand(a: Hand, b: Hand): int =
   let strength = cmp(a.strength, b.strength)
@@ -79,4 +87,92 @@ proc part1(): int =
   for (rank, hand) in enumerate(hands):
     result += (rank + 1) * hand.bid
 
+func strengthJoker(hand: Hand): int =
+  let count = newCountTable(hand.cards)
+
+  let jokers = count[1]
+
+  var regular: CountTable[int]
+  for card, count in pairs(count):
+    if card == 1:
+      continue
+    regular.inc count
+
+  if regular[5] > 0:
+    return five
+  if regular[4] > 0:
+    if jokers == 1:
+      return five
+    return four
+  if regular[3] > 0:
+    case jokers:
+      of 2: return five
+      of 1: return four
+      else: discard
+    if regular[2] > 0:
+      return full
+    return three
+  if regular[2] == 2:
+    if jokers == 1:
+      return full
+    return twoPair
+  if regular[2] == 1:
+    case jokers:
+      of 3: return five
+      of 2: return four
+      of 1: return three
+      else: return pair
+
+  case jokers:
+    of 5: return five
+    of 4: return five
+    of 3: return four
+    of 2: return three
+    of 1: return pair
+    else: return high
+
+func cmpHandJoker(a: Hand, b: Hand): int =
+  let strength = cmp(a.strengthJoker, b.strengthJoker)
+  if strength != 0:
+    return strength
+
+  for (aa, bb) in zip(a.cards, b.cards):
+    let card = cmp(aa, bb)
+    if card != 0:
+      return card
+
+func parseCardJoker(c: char): int =
+  case c:
+    of 'A': 14
+    of 'K': 13
+    of 'Q': 12
+    of 'J': 1
+    of 'T': 10
+    of '9': 9
+    of '8': 8
+    of '7': 7
+    of '6': 6
+    of '5': 5
+    of '4': 4
+    of '3': 3
+    of '2': 2
+    else: 0
+
+func parseHandJoker(text: string): Hand =
+  let parts = text.strip.splitWhitespace
+  (parts[0].map(parseCardJoker), parts[1].parseInt)
+
+func parseHandsJoker(text: string): seq[Hand] =
+  text.strip.splitLines.map(parseHandJoker)
+
+proc part2(): int =
+  let text = readFile("input/day07.txt")
+  var hands = parseHandsJoker(text)
+
+  hands.sort(cmpHandJoker)
+
+  for (rank, hand) in enumerate(hands):
+    result += (rank + 1) * hand.bid
+
 echo part1()
+echo part2()