Cleanup

2020/src/day7.nim

@@ -0,0 +1,51 @@
+import streams, sequtils, pegs, tables, sets, algorithm, strutils
+
+let parser = peg"""
+grammar <- c ' bags contain ' (nc+ / nob) '.'
+nob <- 'no other bags'
+nc <- {\d} ' ' c ' bag' 's'? ', '?
+c <- {\ident ' ' \ident}
+"""
+
+iterator asParsed(s: Stream): (string, seq[string]) =
+  for l in s.lines:
+    if l =~ parser:
+      var d = matches.filterIt(it != "").reversed
+      let key = d.pop
+      yield (key, d)
+
+proc walkUp(t: TableRef[string, HashSet[string]], tar: string): HashSet[string] =
+  if t.contains(tar):
+    let parents = t[tar]
+    echo parents
+    result = parents
+    for p in parents:
+      echo p
+      result = result + t.walkUp(p)
+
+proc part1*(s: Stream): int =
+  var t = newTable[string, HashSet[string]]()
+  for (key, parsed) in s.asParsed:
+    var parents = parsed.filterIt(not(it =~ peg"\d+"))
+    for p in parents:
+      if t.contains(p): t[p].incl(key)
+      else: t[p] = [key].toHashSet()
+  t.walkUp("shiny gold").len
+
+proc walkDown(t: TableRef[string, TableRef[string, int]], tar: string): int =
+  let children = t[tar]
+  for (s, n) in children.pairs:
+    result += n + (n * t.walkDown(s))
+
+iterator asPairChunks(s: seq[string]): (string, int) =
+  for i in countup(0, s.len - 1, 2): yield (s[i], s[i+1].parseInt)
+
+proc part2*(s: Stream): int =
+  var t = newTable[string, TableRef[string, int]]()
+  for (key, parsed) in s.asParsed:
+    echo key, parsed
+    var innert = newTable[string, int]()
+    for (innerkey, n) in parsed.asPairChunks:
+      innert[innerkey] = n
+    t[key] = innert
+  t.walkDown "shiny gold"