private string PartA(IEnumerable <string> data)
{
var gameKid = new GameKid();
var cart = GameKidCart.Parse(data);
gameKid.RunCart(cart);
return("Accumulator = " + gameKid.Accumulator);
}
public bool RunCart(GameKidCart cart)
{
Accumulator = 0;
Address = 0;
UsedInstructions.Clear();
while (true)
{
if (Address >= cart.Instructions.Length)
{
Console.WriteLine("Finished");
return(true);
}
var i = cart.Instructions[Address];
if (UsedInstructions.Contains(Address))
{
Log("INFINITE LOOP", i);
return(false);
}
UsedInstructions.Add(Address);
Log("", i);
switch (i.Operation)
{
case "acc":
Accumulator += i.Argument;
Address += 1;
break;
case "nop":
Address += 1;
break;
case "jmp":
Address += i.Argument;
break;
default:
Log("UNSUPPORTED", i);
return(false);
}
}
}
private string PartB(IEnumerable <string> data)
{
var gameKid = new GameKid();
var cart = GameKidCart.Parse(data);
gameKid.RunCart(cart);
var usedInstructions = gameKid.UsedInstructions.ToArray();
// narrow our search by only modifying instructions we actually use
foreach (var i in usedInstructions)
{
var instruction = cart.Instructions[i];
var prevOp = instruction.Operation;
if (prevOp == "jmp")
{
instruction.Operation = "nop";
}
else if (prevOp == "nop")
{
instruction.Operation = "jmp";
}
else
{
continue;
}
if (gameKid.RunCart(cart))
{
return("Fixed Accumulator = " + gameKid.Accumulator);
}
// undo
instruction.Operation = prevOp;
}
return("Failed");
}
