System.Threading.Tasks var input = File.ReadAllText(Path.Combine(Path.GetDirectoryName(Util.CurrentQueryPath), "..", "day9.txt")).Split(',').Select(int.Parse).ToArray(); bool IntCodeComputer(int[] program, IEnumerable inputStream, out IList outputStream) { var mem = program.Select((p, i) => new { p, i = (long)(i) }).ToDictionary(o => (long)o.i, o => (long)o.p); outputStream = new List(); long ptr = 0; long relativebase = 0; var inp = inputStream.GetEnumerator(); (int[] parmModes, int opcode) op; (int[] parmModes, int opcode) readOpCode(int opCode) => (new[] { (opCode / 100) % 10, (opCode / 1000) % 10, (opCode / 10000) % 10 }, opCode % 100); long getParmVal(int mode, long value) => mode == 0 ? mem[value] : mode == 2 ? mem[relativebase + value] : value; long getParm(long parm) => getParmVal(op.parmModes[parm - 1], mem[ptr + parm]); void setParmVal(int mode, long val, long value) { if (mode == 2) mem[relativebase + val]=value; else mem[val]=value; } void setParm(long parm, long val) => setParmVal(op.parmModes[parm-1], mem[ptr+parm], val); while (mem[ptr] != 99) { op = readOpCode((int)mem[ptr]); switch (op.opcode) { case 1: setParm(3, getParm(1) + getParm(2)); ptr += 4; break; case 2: setParm(3, getParm(1) * getParm(2)); ptr += 4; break; case 3: if (!inp.MoveNext()) return false; setParm(1, inp.Current); ptr += 2; break; case 4: outputStream.Add(getParm(1)); ptr += 2; break; case 5: ptr = getParm(1) != 0 ? getParm(2) : ptr + 3; break; case 6: ptr = getParm(1) == 0 ? getParm(2) : ptr + 3; break; case 7: setParm(3, getParm(1) < getParm(2) ? 1 : 0); ptr += 4; break; case 8: setParm(3, getParm(1) == getParm(2) ? 1 : 0); ptr += 4; break; case 9: relativebase += getParm(1); ptr += 2; break; } } return true; } IntCodeComputer(input.ToArray(), new [] { 1}, out var p1); var part1 = p1.Last(); part1.Dump(); IntCodeComputer(input.ToArray(), new [] { 2}, out var p2); var part2 = p2.Last(); part2.Dump();