2023/04/both.nim

@@ -0,0 +1,54 @@
+import
+  std/math,
+  std/sequtils,
+  std/strformat,
+  std/strutils
+
+import
+  ../../adventofcode
+
+let input = adventofcode.getInput()
+
+when not defined(second):
+  var points = 0
+else:
+  var additionalCards: seq[Natural] = @[]
+
+let lines = input.splitLines()
+for i in 0 .. lines.high():
+  let line = lines[i]
+  when defined(second):
+    if additionalCards.high() < i:
+      additionalCards.add 0
+    let instances = 1 + additionalCards[i]
+  let winningNumsStart = line.find(':') + 1
+  let winningNumsEnd = line.find('|')
+  let winningNums = line[winningNumsStart ..< winningNumsEnd]
+    .split(' ')
+    .filterIt(it != "")
+    .mapIt(parseInt it)
+  let elfNums = line[winningNumsEnd + 1 .. ^1]
+    .split(' ')
+    .filterIt(it != "")
+    .mapIt(parseInt it)
+
+  var duplicata = 0
+  for n in elfNums:
+    if n in winningNums:
+      duplicata.inc()
+
+  when not defined(second):
+    if duplicata > 0:
+      points += 2 ^ (duplicata - 1)
+  else:
+    for j in 1 .. duplicata:
+      if additionalCards.high() < i + j:
+        additionalCards.add 0
+      additionalCards[i + j] += instances
+
+when not defined(second):
+  echo fmt"Answer: {points}"
+else:
+  var originalCardCount = len(lines)
+  var additionalCardSum = sum(additionalCards)
+  echo fmt"Answer: {originalCardCount + additionalCardSum}"