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+# Day Eight: Handheld Halting
+import os, strutils, sequtils
+
+let input: string = paramStr(1)
+var program: seq[string] = split(strip(readFile(input)), '\n')
+
+proc execute(program: seq[string], executed: seq[int]) =
+  var executed = executed
+  var i, time, acc: int = 0
+  while i < len(program) and time < 250:
+    if executed[i] < 0:
+      echo acc
+      break
+    dec(executed[i])
+    var op: string = program[i][0..2]
+    var arg: int = parseInt(program[i][4..^1])
+    case op
+    of "acc":
+      inc(acc, arg)
+      inc(i)
+    of "jmp":
+      inc(i, arg)
+    of "nop":
+      inc(i)
+    else:
+      discard
+    inc(time)
+  if i >= len(program):
+    echo acc
+
+execute(program, repeat(0, len(program)))
+
+for i, instruction in program:
+  var program = program
+  program[i] =
+    if contains(instruction, "jmp"):
+      replace(instruction, "jmp", "nop")
+    else:
+      replace(instruction, "nop", "jmp")
+  execute(program, repeat(100, len(program)))