Pausing work on day8p2

2020/src/day8.nim

@@ -2,26 +2,55 @@ import streams, strutils, sequtils, sets
 
 type
   InstructionType = enum nop acc jmp
-  Instruction = ref object of RootObj
+  Instruction = object
     instruction: InstructionType
     arg: int
+  HandheldState = object
+    bootcode: seq[Instruction]
+    acc: int
+    pointer: int
+    running: bool
+
+proc newHandheld(bootcode: seq[Instruction], acc = 0, pointer = 0, running = true): HandheldState =
+  HandheldState(bootcode: bootcode, acc: acc, pointer: pointer, running: running)
 
 proc instructions(s: Stream): seq[Instruction] =
   toSeq(s.lines).mapIt(it.split).mapIt(Instruction(instruction: parseEnum[InstructionType](it[0]), arg: parseInt(it[1].replace("+"))))
 
+proc stepHandheld(state: var HandheldState) =
+  if state.pointer >= state.bootcode.len:
+    echo "Reached end of instructions"
+    state.running = false
+  let i = state.bootcode[state.pointer]
+  case i.instruction:
+    of acc: inc state.acc, i.arg
+    of jmp: inc state.pointer, i.arg; return
+    else: discard
+  inc state.pointer
+
 proc part1*(s: Stream): int =
   var hasRun = initHashSet[int]()
-  var p = 0
-  let code = s.instructions
-  while true:
-    if hasRun.contains p: return result
-    hasRun.incl p
-    let i = code[p]
-    case i.instruction:
-      of acc: inc result, i.arg
-      of jmp: p += i.arg; continue
-      else: discard
-    inc p
+  var handheld = newHandheld(s.instructions)
+  while handheld.running:
+    stepHandheld handheld
+    if hasRun.contains handheld.pointer: return handheld.acc
+    hasRun.incl handheld.pointer
+
+proc correctingHandheld(state: var HandheldState) =
+  if state.pointer >= state.bootcode.len:
+    echo "Reached end of instructions"
+    state.running = false
+  let i = state.bootcode[state.pointer]
+  case i.instruction:
+    of acc: inc state.acc, i.arg
+    of jmp: inc state.pointer, i.arg; return
+    else: discard
+  inc state.pointer
 
 proc part2*(s: Stream): int =
-  0
+  var hasRun = initHashSet[int]()
+  var handheld = newHandheld(s.instructions)
+  while handheld.running:
+    stepHandheld handheld
+    if hasRun.contains handheld.pointer: return handheld.acc
+    hasRun.incl handheld.pointer