106 lines
4.6 KiB
Erlang
106 lines
4.6 KiB
Erlang
-module(day23).
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-export([start/0]).
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value_or_register(X, Registers)
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when X >= <<"a">>, X =< <<"z">> -> maps:get(X, Registers, 0);
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value_or_register(X, _Registers)
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-> { NewValue, _ } = string:to_integer(X),
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NewValue.
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format_input(Input)
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-> lists:map(fun(X) -> [A|Args] = re:split(X, " "), { A, Args } end, re:split(Input, "\n")).
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assemble(Input)
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-> Instructions = format_input(Input),
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assemble(Instructions, length(Instructions), 1, 0, maps:new()).
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debug_assemble(Input)
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-> Instructions = format_input(Input),
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assemble(Instructions, length(Instructions), 1, 0, maps:put(<<"a">>, 1, maps:new())).
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assemble(_Instructions, MaxInstructions, Ip, LastFrequency, Registers)
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when Ip < 1; Ip > MaxInstructions -> { LastFrequency, Registers };
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assemble(Instructions, MaxInstructions, Ip, LastFrequency, Registers)
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-> { Op, Args } = lists:nth(Ip, Instructions),
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%io:fwrite("ip ~p op ~p args ~p~n~p~n", [Ip, Op, Args, Registers]),
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case Op of
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<<"add">> ->
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[Src,Dest|_] = Args,
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ExistingValue = maps:get(Src, Registers, 0),
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NewValue = value_or_register(Dest, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, maps:put(Src, ExistingValue + NewValue, Registers));
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<<"sub">> ->
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[Src,Dest|_] = Args,
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ExistingValue = maps:get(Src, Registers, 0),
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NewValue = value_or_register(Dest, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, maps:put(Src, ExistingValue - NewValue, Registers));
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<<"jnz">> ->
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[Src,Dest|_] = Args,
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SrcValue = value_or_register(Src, Registers),
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NewValue = value_or_register(Dest, Registers),
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if SrcValue /= 0 -> assemble(Instructions, MaxInstructions, Ip + NewValue, LastFrequency, Registers);
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true -> assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, Registers)
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end;
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<<"jgz">> ->
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[Src,Dest|_] = Args,
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SrcValue = value_or_register(Src, Registers),
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NewValue = value_or_register(Dest, Registers),
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if SrcValue > 0 -> assemble(Instructions, MaxInstructions, Ip + NewValue, LastFrequency, Registers);
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true -> assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, Registers)
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end;
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<<"mod">> ->
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[Src,Dest|_] = Args,
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ExistingValue = maps:get(Src, Registers, 0),
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NewValue = value_or_register(Dest, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, maps:put(Src, ExistingValue rem NewValue, Registers));
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<<"mul">> ->
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[Src,Dest|_] = Args,
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ExistingValue = maps:get(Src, Registers, 0),
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NewValue = value_or_register(Dest, Registers),
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Registers2 = maps:put("mul_count", maps:get("mul_count", Registers, 0) + 1, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, maps:put(Src, ExistingValue * NewValue, Registers2));
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<<"rcv">> ->
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[Dest|_] = Args,
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NewValue = value_or_register(Dest, Registers),
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if NewValue /= 0 -> LastFrequency;
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true -> assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, Registers)
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end;
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<<"set">> ->
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[Src,Dest|_] = Args,
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NewValue = value_or_register(Dest, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, maps:put(Src, NewValue, Registers));
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<<"snd">> ->
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[Dest|_] = Args,
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NewValue = value_or_register(Dest, Registers),
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assemble(Instructions, MaxInstructions, Ip + 1, NewValue, Registers);
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<<>> ->
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io:fwrite("invalid instruction: ~p~n", [{ Op, Args }]),
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assemble(Instructions, MaxInstructions, Ip + 1, LastFrequency, Registers)
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end.
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is_prime(Check)
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-> is_prime(Check, 2, math:sqrt(Check)).
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is_prime(Check, Min, _Max)
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when Check rem Min == 0 -> false;
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is_prime(Check, Min, Max)
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when Min > Max -> Check /= 1;
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is_prime(Check, Min, Max)
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-> is_prime(Check, Min + 1, Max).
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get_num_nonprimes(Start, End)
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-> get_num_nonprimes(Start, End, 1, is_prime(Start)).
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get_num_nonprimes(Start, End, Count, _IsPrime)
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when Start == End -> Count;
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get_num_nonprimes(Start, End, Count, IsPrime)
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when IsPrime -> NewStart = Start + 17,
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get_num_nonprimes(NewStart, End, Count, is_prime(NewStart));
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get_num_nonprimes(Start, End, Count, IsPrime)
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when not IsPrime -> NewStart = Start + 17,
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get_num_nonprimes(NewStart, End, Count + 1, is_prime(NewStart)).
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start()
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-> { ok, File } = file:read_file("problem"),
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io:fwrite("~p~n", [ assemble(File) ]),
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%io:fwrite("~p~n", [ debug_assemble(File) ]).
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io:fwrite("~p~n", [ get_num_nonprimes(109900, 126900) ]).
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