2022/07/both.nim

@@ -0,0 +1,105 @@
+import
+  std/strutils,
+  std/strformat,
+  std/tables
+
+import
+  ../../adventofcode
+
+proc `/`(base, tail: string): string =
+  if tail == "..":
+    let sep = base.rfind('/')
+    if sep > 0: return base[0 ..< sep]
+    else: return "/"
+  else:
+    if base[^1] == '/':
+      return base & tail
+    else:
+      return base & "/" & tail
+
+type
+  PseudoFileKind = enum
+    pfFile, pfDir
+  PseudoFile = ref object
+    case kind: PseudoFileKind
+    of pfFile:
+      size: Natural
+    of pfDir:
+      fileNames: seq[string]
+proc newPseudoFile(size: Natural = 0): PseudoFile =
+  result = PseudoFile(kind: pfFile, size: size)
+proc newPseudoDir(): PseudoFile =
+  result = PseudoFile(kind: pfDir)
+
+let input = adventofcode.getInput()
+var files = initTable[string, PseudoFile]()
+var dirSizes = initTable[string, Natural]()
+var cwd = "/"
+var cwdObj = newPseudoDir()
+files["/"] = cwdObj
+
+proc computeSize(path: string): Natural =
+  if not files.hasKey path: return
+  let file = files[path]
+  case file.kind
+  of pfFile: return file.size
+  of pfDir:
+    if dirSizes.hasKey path:
+      return dirSizes[path]
+    for name in file.fileNames:
+      result += computeSize(path / name)
+    dirSizes[path] = result
+
+for line in input.splitLines:
+  let args = line.splitWhitespace()
+  if args[0] == "$":
+    if args[1] == "cd":
+      if args[2][0] == '/':
+        cwd = args[2]
+      else:
+        cwd = cwd / args[2]
+      when not defined(release):
+        echo fmt"{cwd = }"
+      
+      if files.hasKey cwd:
+        cwdObj = files[cwd]
+      else:
+        cwdObj = newPseudoDir()
+      files[cwd] = cwdObj
+  else:
+    if args[1] notin cwdObj.fileNames:
+      cwdObj.fileNames.add args[1]
+    if args[0] == "dir":
+      let dir = newPseudoDir()
+      files[cwd / args[1]] = dir
+    else:
+      let file = newPseudoFile(size=parseInt args[0])
+      files[cwd / args[1]] = file
+
+when not defined(second):
+  var sum = 0
+
+  discard computeSize "/"
+  for path, dirSize in dirSizes:
+    if dirSize < 100_000:
+      sum += dirSize
+
+  echo fmt"Answer: {sum}"  
+else:
+  import
+    std/algorithm,
+    std/sequtils
+
+  const maxFsSize = 70_000_000
+  const updateSize = 30_000_000
+
+  let currFsSize = computeSize "/"
+  let requiredSize = currFsSize - (maxFsSize - updateSize)
+  when not defined(release):
+    echo fmt"{requiredSize = }"
+
+  let dirSizesSeq = sorted toSeq dirSizes.values()
+  for size in dirSizesSeq:
+    if size > requiredSize:
+      echo fmt"Answer: {size}"
+      break