day03

2022/day03/day03.nim

@@ -0,0 +1,28 @@
+import std/[os, math, sequtils, setutils, strutils, sugar, tables]
+
+const letters = toSeq('a'..'z').concat(toSeq('A'..'Z'))
+const priorities = zip(letters, toSeq(1..52)).toTable
+
+proc commonType(sacks: varargs[string]): char =
+  let sets = sacks.map(x => x.toSet)
+  let intersection = sets.foldl(a * b)
+  intersection.toSeq[0]
+
+proc compartments(sack: string): seq[string] =
+  let
+    sackMid = sack.len div 2
+    comp1 = sack[0..<sackMid]
+    comp2 = sack[sackMid..^1]
+  @[comp1, comp2]
+
+let sacks = stdin.readAll().strip().splitLines()
+
+var groups: seq[seq[string]]
+if paramStr(1) == "1":
+  groups = sacks.map(compartments)
+elif paramStr(1) == "2":
+  groups = sacks.distribute(sacks.len div 3)
+
+let types = groups.mapIt(it.commonType)
+let prios = types.mapIt(priorities[it])
+echo sum(prios)